No one has an obligation to “assimilate” into a different culture, regardless of what piece of dirt they happen to be standing on. People don’t acquire an obligation to wear what you wear, eat what you eat, speak the language you speak, and think what you think, just because they exist in close proximity to you. You might wish they would, and it might help them if they did, but the only obligation they have to you is to not commit fraud or aggression against you. That’s all.
Americans are so damn pompous sometimes when it comes to the “assimilation” thing, bitching and moaning about other people coming to the U.S. and choosing to hang around others like themselves, and dressing, thinking, speaking and behaving as they did when they were in some other country. Which, by the way, is exactly what most Americans do when they go to other countries: they keep speaking, dressing, acting and thinking like Muricans.
What makes the xenophobia particularly ridiculous is that people of European descent, especially those now living in the U.S. southwest, are even insisting that the people who have lived there for thousands of years “assimilate” to the culture of the invaders. What the hell?
Yes, most people prefer to be around others that have a lot in common with them. People like to be in familiar surroundings. That doesn’t make anyone evil. An American isn’t evil for preferring to be around people who speak his language and share his customs, culture, views, etc. And guess what. The people who come here from other places aren’t evil for preferring the same damn thing for themselves. The only evil comes when someone decides to initiate violence against someone else. Unless and until that happens, you can bellyache all you want, but you have no right, on your own or via “government,” to force anyone to “assimilate” to anything.