I appreciate your response, and wanted to make a few quick points to your uncharacteristically (for HN) reasonable rebuttal. I just want to give a little nutshell version of my thoughts here because this is a very long and nuanced discussion that might not work best on HN.
> I don’t find this to be a useful line of thought most times because it’s extraordinarily nationalistic.
Ultimately as a philosophy, I'm not super in favor of the concept of nations either. However, so long as we exist in a world with governments, somebody is making your area's rules. If it's not your group, it's outsiders who vote with their feet and who are going to decide it for you, to their own economic and cultural advantage and not necessarily yours.
Completely unfettered mass migration would not be as objectionable if we were living in a more libertarian system: no welfare state, no subsidized transportation, no rules preventing the right of free association, etc. Then everybody is just their own person who poses no potential of financial burden on you with their presence and who you're not forced to associate with if you don't want to.
The problem is that you can't have both a massive welfare state and unfettered immigration without posing many significant problems for the native population.
> What logic justifies saying that migrants are driving out current inhabitants?
Please note that I didn't explicitly make the argument that migrants are driving out current inhabitants. I simply made an economics point about housing prices. All other things being equal, the demand for housing increasing would tend to increase the price, right?