Assimilation is a right-wing fascist kind of thing that goes directly against Individualism, Freedom, and Liberty to be who you are. Mutual respect for those three concepts is what you need and not what you want, a mass of unthinking, xenophobic, nationalistic, flag-wavers afraid of free-thinking people with respect for their cultural heritage within the larger society.
It's no shock that free-thinkers scare the hell out of you, anyone who thinks at all scares the hell out of you since you are unable to.