There's no fundamental reason why America's ability to integrate cultures couldn't be replicated in Europe. It's just a cultural choice not to. There's not any excuse for it.

Just like the current xenophobic attitudes among some in the US is a choice and was a choice in the past. None of this is excusable, none of it is inevitable. And I have little patience for "realists" who carry water for the idea that xenophobia is inevitable and unchangeable.

And not that it matters to the discussion of whether it's inevitable or not, but Americans are more welcoming of immigrants: https://www.nytimes.com/2015/12/09/business/international/fo... and have lower demonstrated racism than most of Europe: https://www.washingtonpost.com/news/worldviews/wp/2013/05/15...