If only Americans think we're the good guys, then why does everyone want to live here?

Well, first, that's two overgeneralizations.

But, second, often precisely because they think we’re the bad guys.

If you see the world as dominated by an evil, overwhelmingly powerful empire that uses violence in a way that shows no concern for the continuation or quality of human life outside of the metropole then, even if it is bigoted, repressive, and unjust within the metropole, you still want to be in the metropole rather rhan peripheries.