The official number of Covid related deaths is only 4600 in China but almost exactly 1 million in the US so far and China has 3-4 times higher population.
China's statistics might not be accurate (for critical reports see reports, the true number of Covid deaths could be much higher in China). Also, some of the US fatalities of Covid would have died from other courses in the mean time, excess death rate is smaller. However, if you believe that the numbers are not too much off that means that China would have managed to avoid up to 3 million deaths in comparison to the US in the last two years. That would be quite an achievement.
We will likely never find out with certainty about the true number of Covid deaths in China, but I would say that saving lives on the order of millions can justify the taken quarantine measures in principle (without the excesses). It even might be seen as a bargain, depending on how exactly you balance personal freedom (to spread germs) and public health solidarity. Some people would actually applaud how China treated Covid so far and would rather stress that while effective, the rest of the world was simply not capable of such a discipline. (Other regions like Japan also did rather well, so it might be more complicated.) On the other hand quarantines put additional stress on people and lower the quality of life especially if done in the very rigid Chinese way.
Additionally, the Chinese vaccines aren't that efficient as the Western ones so keeping strict quarantine rules may still look like the only possibility to avoid a large number of deaths in China unless they want to use other vaccines, which they probably should. Non-Chinese very effective vaccines are currently not officially approved in China.
One open question is why only so few of the elder Chinese people are fully vaccinated. The authoritarian Chinese government would not be able to force elder Chinese to take their vaccine? That's hard to believe.
On the other hand, the currently dominant omicron variant seems to be very infectious but not so fatal as previous variants. The zero cases strategy of the Chinese government might not be sustainable under these circumstances.
In the end, you want to either have an effective vaccine or treatment because otherwise it will be quarantines forever and that might be seen as a too high price to pay in the future. (It's not as if the Chinese population has much say in that.)
That doesn't mean though that China needs to separate children from parents or supply insufficient amounts of food to people during a quarantine. Both is not necessary for keeping the number of Covid infections down and should rightly be condemned. Keeping Covid numbers down in China with the Omicron variant may prove illusory. As soon as any quarantine ends, Covid will come back immediately. The alternatives are only to either live with it or stay under quarantine forever, in which case most likely the overwhelming majority of people would choose to live with the virus.
And related deaths like medical emergencies or suicides during quarantines or starvings during a quarantine in China must be counted towards the number of Covid related deaths as well.
To contrast China's policy:
In the area where I live we never had zero Covid cases during the whole pandemics and people seem to have decided now to live with it with numbers going extremely high now. Approximately 10% (!) of the population was infected at the same time at the peak of the last wave and measures against Covid have lately been canceled lately amidst a Covid surge. Even wearing masks, which is a very cheap and effective measure, is not mandatory anymore except in public transport.
The vaccination rate is reasonably high especially among elders (>90%). Consequently people continue to die from Covid in moderate but significant numbers, but there is no quarantine anymore. The cumulative Covid death rate over the last two years here is about half that of the US, so a bit better but not great. With stronger and longer health measures (like mask mandates for example) very likely lives could have been saved but the costs for that must have been seen as too high, especially lately.