Would you make this same argument for Americans moving en masse to a small country with a rich heritage, and promptly trying to erase it? It happened in the past, doesn't make it right.
Is if it sucks, and has demonstrably ruined other cities.
But seriously, “demonstrably ruined” is a very one note take and not really useful. People deserve to have their culture respected and it’s totally fine to take it with you. That’s the whole point of American individualism. It wasn’t supposed to be about guns and group think it was supposed to be self determination and the freedom to make your own path. People come to America for freedom, not because they want to conform. When’d we lose that?
That sounds like most cities.