So, on one hand, this is an excusable policy (as in, there are already immigration law apologists in here making excuses for it).
On the other hand, I don't like immigration control as a concept - countries should not operate like hereditary country clubs, and people should not have less freedom of movement than bags of money. More self-interestedly, I'm an American, and I know my country's infrastructure - both political and otherwise - is failing horribly. I don't want out yet, but I know I'm going to need out at some point in my lifetime. So every time I see a favorable country locking their doors, I shudder.
There's probably going to be at least one reply from a European saying this is a good thing - that American citizens (or, if things get really bad, American refugees) should be denied entry, under the theory that immigration is a welfare / free money for thieves program and that letting people leave destroyed countries just rewards people for destroying them.
This is, of course, bullshit, both because it's victim blame-y, AND because it covers up a shortcoming of the country making the excuse. The real reason countries try to avoid taking in refugees is that most countries are built like hereditary country clubs. They don't take in immigrants, so they don't know how to integrate immigrants. Japan in particular has a community of poorly-integrated American emigrants that largely just stick to themselves.
America, ironically enough, is one of the few countries that actually cracked the code on immigration. We used to have really generous family reunion visa programs, we have basically every immigrant population you can think of in every major city, and immigrants that come here integrate way better than ones that go to Europe. So it's not like countries have to be restrictive on immigration.
Instead, what I'm seeing is that immigration is being used by politicians to distract from their own countries' failings. It's the same story as what happened in America[1]: when shit breaks, people get rich off selling the fix, and so they pay[0] politicians to keep the system broken enough that they can continue profiting off of it. But this only works if you give the people some kind of excuse. The politics of scarcity are brutal, but scarcity becomes a far easier sell if you have a scapegoat. Some magical source of systemic burden you can shed without backlash. "The state-run insurance system isn't broken because we don't pay our doctors, it's broken because we have too many poor patients from other countries!"
[0] Not necessarily in the "bribery is free speech" way America does it, of course.
[1] Which would indicate to me that perhaps leaving the country is a fool's errand, if every other country is on the same curve.