People who have things in common, even people who’d be best friends, even those who are best friends, can compete for resources and cause problems just by existing.

Like, extreme case, not enough food in zombie apocalypse scenario and you find more survivors, doesn’t matter how good those people are it’s a problem that they’re part of the group.

It doesn’t mean the people are enemies, just that their presence is a problem.

Now, it’s probably the case that they should be allowed to move from country to country because otherwise you don’t have competition between countries to attract people. People need to be able to choose their associations in order to be free, and people should be able to move countries.

It’s a free market in that sense, and the suffering of people whose home country’s resources are strained by immigration isn’t as powerful as the suffering these people are leaving to come here, and when those two levels equalize the immigration pressure will stop. People will be going the other direction just as much.

And I think that’s all totally fair. I think people should be able to vote with their feet and go wherever is best for them.

But then being similar or dissimilar, good or bad, none of that is necessary for it to create simple resource competition problems.