It's itself a neutral-to-good thing probably but has negative as well as positive side-effects. It's likely better for a country that's otherwise culturally diverse than the alternative; were America more homogeneous in other ways that would not be the case.
I'm a bit surprised you say that, since you've reacted with horror to some very "American" quotes and comments on this before.
It's good because it prevents overt "tribalism"/sectarianism, and it's good for social cohesion in society. It's bad for communities and social cohesion within communities.
Rural areas in Minnesota and North Dakota are some of the most "socially cohesive" places you can ever find.