the US suffers from systemic historic racism that they are struggling to get rid of, but they have always been a mix of cultures where some aspects of foreign cultures are assimilated and accepted and other aspects disappear as the immigrants adapt.
europe suffers from xenophobia and general difficulty to integrate foreign cultures. being traditionally a single culture there is very little assimilation of foreign cultures (mostly some food items) and immigrants are expected to adapt fully to the local culture, without any allowance to keep aspects of their own culture with few exceptions.
in my opinion this leads to immigrants in europe holding on to their own culture more than they would in the US making integration even more difficult.
Wait, what specifically does? Why do you think gypsies have not integrated yet in any countries they are in? Be it Canada, Bulgaria, Poland, Hungary, Germany, etc.
the expectation to assimilate our culture and fully give up theirs.
Why do you think gypsies have not integrated
i'd believe this is mainly because they are nomadic, which is something that we seem to have a hard time accepting, or even tolerating. for me this is one aspect of their culture that we should celebrate and support. but we don't.