What makes the Global Compact for Migration so controversial?

Question

According to recent news:

The UN General Assembly endorsed a sweeping accord to ensure safe and orderly migration on Wednesday, overriding opposition from five countries, including the United States and Hungary. It was approved by a vote of 152-5 with Israel, the Czech Republic and Poland also voting “no” and 12 countries abstaining.

However there don't seem to be any particularly controversial sections within the official text of the agreement, especially compared to previous treaties such as the 1951 Refugee Convention. So why exactly did several states vote against adopting this resolution?

Answer 1

Migration is controversial so the compact is controversial.

If one of the basis of your political discourse is that immigration is the root of all social evils, painting the compact that as a threat that will force governments to accept immigrants against their will gives for some political points when you reject it¹.

So, rejecting the compact would appeal to the governments who got elected on this premise, specially if the people are protesting the government. It allows the governments to move the debate towards the immigration issue and paint themselves as defenders of the national independence and sidestep other issues.

Of course, this is not restricted to governments, as political parties everywhere have mischaracterized the Compact in the same way in order to attack the government.

To use a quote taken from someone else's link

The Crown Law Office and the Ministry of Foreign Affairs and Trade had provided legal advice that confirmed the UN cooperation framework was neither legally binding nor constraining on the country setting its own migration policies, he[New Zeland Foreign Minister Winston Peters] said.
"The legal advice from Crown Law is not surprising but is important advice in debunking falsehoods or misguided perceptions being spread about the implications of this framework."

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¹Of course, you could argue that those who signed it are trying to get points for signing a document that says "we are nice people who treat people nicely" but does not compromise them to any practical measure.

Answer 2

The word controversial might be a bit misused here, because as you said 152-5 is probabaly not a controversial thing. Now assuming you might mean within the countries that voted no, let’s take the US for example. First, Our current president has restrictive views of immigration. In general, he feels his base is motivated by ideas of less migration. Second, he also leans isolationist. I don’t mean that sensationally, he just does not tend to respect international authority as much as others. Even if some of the langauage in this treaty is non controversial, we all know most people will not read it and his base does not want to see the United States attached to this, because of these two key principles they have.

Answer 3

Short short version: the "Compact" is a threat to decision making by sovereign countries.

From https://www.stuff.co.nz/national/politics/109486713/new-zealand-votes-for-un-migration-compact-after-legal-advice:

A number of countries, including the United States and Australia, pulled out of the agreement because of the potential impact on the decision-making of individual countries.

And National Party leader Simon Bridges said if his party was in government, it would pull out of the compact because of its potential to restrict New Zealand's ability to set its own migration and foreign policy.