If the (reopened, but still rather unclear to me) question is why is the news media prioritizing this, the answer is (duh) because it's new.
If the question is why is China prioritizing this, e.g. building an entire hospital for it in Wuhan... look no further of how the problem is being politicized elsewhere:
Commerce Secretary Wilbur Ross said Thursday that the coronavirus outbreak in China will help “accelerate the return of jobs to North America.”
“Well, first of all, every American’s heart has to go out to the victims of the coronavirus. So I don’t want to talk about a victory lap over a very unfortunate, very malignant disease. But the fact is, it does give businesses yet another thing to consider when they go through their review of their supply chain,” Ross said during an interview with Fox Business Network’s Maria Bartiromo.
So China clearly has an image problem with this. Likewise, they were quite unhappy with the Denmark's Jyllands-Posten (yes the one with the Muhammad cartoon controversy) when they posted this:
On the more scientific tack:
The World Health Organisation (WHO) declared on Thursday (Jan 30) that the coronavirus epidemic in China now constitutes a public health emergency of international concern (PHEIC).
The WHO first introduced PHEIC as part of the 2005 International Health Regulations after the Sars virus in 2003.
Sars was recognised as a "global threat" by the WHO in mid-March 2003. It infected about 8,000 people worldwide and killed 774 people over seven months.
Dr Tedros Adhanom Ghebreyesus, WHO director-general, announced the decision after a meeting of its Emergency Committee, an independent panel of experts, amid mounting evidence of the virus spreading to some 18 countries. [...]
"Let me be clear, this declaration is not a vote of no confidence in China," he said.
"Our greatest concern is the potential for the virus to spread to countries with weaker health systems," he added.
The WHO defines a global health emergency as an "extraordinary event" that is "serious, unusual or unexpected".
So as far as WHO is concerned, this seems as bad as SARS was, insofar.
Frankly the only country that seems to have done something unusual has been the US:
on Friday, US Health and Human Services Secretary Alex Azar declared that the 2019-nCoV outbreak constitutes a public health emergency in the United States and that international citizens who have traveled anywhere in China during the previous 14 days would be denied entry to the United States. In addition, any US citizen who had been in China’s Hubei province during that period would be subject to quarantine for up to 14 days for medical observation.
At the CDC press briefing, Messonnier said that the agency, under statutory authority of the Health and Human Services secretary, had issued federal quarantine orders for all 195 repatriated individuals who were evacuated on January 29 from Wuhan, China, to a California military base. “While we recognize this is an unprecedented action, we are facing an unprecedented public health threat,” she said.
The action marks the first time in 50 years that the United States has issued a mandatory quarantine order.
Whether the US knows something that China or the WHO don't or this is simply a reflection of more Trumpian times ("America first" etc.), I guess will find out later on.
There are some recent numbers (as Bryan Krause comments) that indicate this could be a bigger problem than SARS. In a Reuters graphic:
Another (medical) source made a (more) useful comparison with SARS and the "swine flu":
As the new coronavirus continues to cross international borders, the two key questions on public health officials’ minds are: ‘How deadly is it?’ and ‘Can it be contained?’.
The two outbreaks in recent memory that give the most insight into these questions are the 2002-2003 SARS outbreak, which spread from China to 26 other countries but was contained after eight months, and the 2009 H1N1 influenza pandemic, which originated in Mexico and spread globally despite all containment efforts. [...]
A key characteristic to examine in these two disease profiles is whether symptoms appear before transmissibility – i.e. at a point when patients are not yet able to infect others – or the other way around. For SARS, symptoms usually appeared before transmissibility. This feature made SARS containable.
For the 2009 H1N1 pandemic, transmissibility appeared about one day before symptoms. This meant that even the best control measures missed 20% of transmitting patients, simply because they showed no symptoms.
Is the current epidemic more similar in severity and transmissibility to the SARS outbreak or the 2009 flu pandemic? I am a professor of biology who studies the evolution and epidemiology of infectious disease, and in my view, in late January 2020, we do not yet have enough solid evidence to answer this question.
I'm not sure if the last question has been answered, but countries like the US and Australia, Russia, Japan seem to act as if it has been answered (in the unfavorable direction).
To make this part of the plot a bit thicker, there was a paper published at the end of January claiming that asymptomatic transmission was observed. Interestingly the publication of this paper coincided with the institution of some of the aforementioned travel bans. But the paper was revealed to be flawed a few days later:
A paper published on 30 January in The New England Journal of Medicine (NEJM) about the first four people in Germany infected with a novel coronavirus made many headlines because it seemed to confirm what public health experts feared: that someone who has no symptoms from infection with the virus, named 2019-nCoV, can still transmit it to others. That might make controlling the virus much harder.
[...] “There’s no doubt after reading [the NEJM] paper that asymptomatic transmission is occurring,” Anthony Fauci, director of the U.S. National Institute of Allergy and Infectious Diseases, told journalists. “This study lays the question to rest.”
But now, it turns out that information was wrong. The Robert Koch Institute (RKI), the German government’s public health agency, has written a letter to NEJM to set the record straight, even though it was not involved in the paper.
[...] the researchers [of the first NEJM paper] didn’t actually speak to the woman before they published the paper. The last author [...] says the paper relied on information from the four other patients: “They told us that the patient from China did not appear to have any symptoms.” Afterward, however, RKI and the Health and Food Safety Authority of the state of Bavaria did talk to the Shanghai patient on the phone, and it turned out she did have symptoms while in Germany. According to people familiar with the call, she felt tired, suffered from muscle pain, and took paracetamol, a fever-lowering medication. (An RKI spokesperson would only confirm to Science that the woman had symptoms.)
The fact that the paper got it wrong doesn’t mean transmission from asymptomatic people doesn’t occur. Fauci, for one, still believes it does. "This evening I telephoned one of my colleagues in China who is a highly respected infectious diseases scientist and health official," he says. "He said that he is convinced that there is asymptomatic infection and that some asymptomatic people are transmitting infection." But even if they do, asymptomatic transmission likely plays a minor role in the epidemic overall, WHO says. People who cough or sneeze are more likely to spread the virus, the agency wrote in a situation report on Saturday. “More data may come out soon. We will just have to wait,” Lipsitch [an epidemiologist at the Harvard T.H. Chan School of Public Health] says.
As much as China has criticized the quarantines and travel bans in other countries, they have pretty much done the same internally, with people from Hubei being subjected to similar measures... and even the streets of Beijing looking rather empty nowadays. Somewhat similar to their response to the SARS outbreak, China went from censorship and official denial to authoritarian overdrive (some of which of questionable efficacy).
The virus-control campaign explains a splash of colour on Weiji’s almost-empty main street, a red banner urging locals to be tested. It reads: “Find It Early! Treat It Early! Medical Fees All Free!”
That encouraging, cajoling sign is buttressed by a dose of coercion. The village’s fresh-faced Communist Party chief, who wears a smart black windbreaker, describes instructions from higher-ups. Cars with Hubei number plates are to be turned away, and migrants returning from that province sent back. Those who made it home to Weiji before controls were imposed on January 20th must submit to temperature checks twice a day and remain indoors in their family homes, with no visitors allowed. Foreign experts may debate the medical efficacy of mass quarantines, but locals describe a sense of comfort from doing something to fight what President Xi Jinping calls a “devil” virus. [...]
Many villages have shut themselves off from outsiders using barricades made of freshly-dug earth, lumps of concrete or, in one case, a parked tractor (an example outside the village of Wangyoufang, southern Henan, is pictured). At one such roadblock, old men in disposable face-masks sit at a wooden office desk, a pot of thermometers in front of them. The campaign is an odd mix of high and low technology. Henan police questioning this reporter were able to summon up his photograph and details by tapping his Chinese telephone number into a mobile device. But electronic thermometers gave very different readings in the space of a few seconds—an alarming flaw when even a hint of fever at a checkpoint can result in 14 days of quarantine.
Interesting too perhaps, the WHO was also critical [of China this time] two weeks ago:
“The lockdown of 11 million people is unprecedented in public health history, so it is certainly not a recommendation the WHO has made,” he [Gauden Galea, the World Health Organization (WHO) representative in China] said, adding authorities had to wait to see how effective it is.
But sealing off Wuhan is “a very important indication of the commitment to contain the epidemic in the place where it is most concentrated”, Galea said.
According to some experts, the widespread quarantine and travel restrictions within China are the brainchild of Zhong Nanshan, who also had a leading role in the management of the SARS outbreak. The lockdowns are said to have been personally approved by president Xi.