> I won't touch on the history that usually led to that surplus in the first place
You literally just did, only in that comedically vapid hand-wavy, bullshit way that's so common.
Germany got obliterated during two world wars and is a power house, again. Japan got nuked twice and is a powerhouse. China is now an absolute powerhouse. South Korea a powerhouse.
It turns out that when you stop doing the "woe am I! white man stole all the good stuff...somehow" horseshit, you can actually improve your lot.
Like if your country is a hyper-corrupt open-air garbage dump, maybe stop pointing at other countries as the cause and fix your own shit. And when enough people from that sort of culture -- and it is a culture, and culture can be judged, and some are simply garbage -- move to infinitely better countries, invariably they start dragging their busted, tragedy of the commons behaviours. They should be on the first mode of transport back.
> why is there an issue?
Because the myth of the advantage of immigration -- the thing that gets a population to tolerate it as a wonderful solution for everyone -- in no universe matches the reality. It's a lie, and it's why so many countries have taken a super-hard turn to the right. What should be a worthwhile program to bring skills and perspective instead turns into a flood where you end up with ghettos of the source country, with all the same problems. No thanks.
Canada almost took a turn to the right, but the leading party actually made significant changes. Not nearly enough (the entire TFW program is just an enormous fraud, top to bottom, zero elderly relatives should ever come here, every non-citizen that commits even a minor crime should be ejected at first cause, the refugee program needs to have a 95%+ rejection rate, and so on). Canadians were done with the lie, so changes were made.
Turns out we still have millions of people who need to leave the country.
> Isn't the - ideal of the - "free market" supposed to be a thing all should aspire to?
A free market is that there are a few countries that are extremely desirable, and a lot of, sorry to say, shitholes with garbage cultures. You should be extraordinary to have the privilege of moving to one of the better countries, and your behaviour when you get there had better be exemplary. Somehow we got in the situation where millions of dregs are flooding every Western country and recreating the shithole they left. In that case, shut it down, which again is happening everywhere.
That is the free market. People were sold a lie, and they're turning against it.