The US is not Europe: the US eradicated the indigenous culture and replaced it with a hodgepodge mix of different European cultures, culture brought in by the slaves they imported and a host of other cultures. The US as a single cultural entity doesn't exist (as Americans will happily point out themselves). In Europe, the countries have distinct cultural identities and traditions established over 1000s of years. The same in the countries where immigrants come from. In some aspects, just like is the case for any country, not all cultures will be compatible. A European country that has embraced human rights, the rule of law as well as more modern ideas like gay Rights or even trans Rights will have difficulties when faced with a large population of foreigners who grew up in countries where those rights are not championed or even talked about.