Such is the effect of "multiculturalism" when it takes the place a diversity. You can have a diverse nation of various ethnicity, so long as a singular culture is created from the joining of those cultures and every group sees themselves as part of the nation first, their ethnic group second. When you try and compensate everyone through multiculturalism, each group will always feel like they are owed more or that they should be on top. To get their way they dig up past atrocities committed to them, victimize themselves, and try to move up the ladder. In Germany, people are too afraid of being called a Nazi to support immigration reform, Caucasian Americans are to scare to call African Americans out on their racism, and British people feel bad about messing with Irish people.
Instead of getting productive members of a society, you have groups of people that will take any perceived slight, twist it, and try and make it look like they are owed something. It is sad, each of these groups will ostracize those who just want to get along with their neighbors and work like everyone else for what they want.
EDIT: Not saying we should go about burning, executing, or kicking people out. Just saying we need to realize that we can't make everyone happy and should be reasonable when looking at issues of hate and discrimination
(Don't stone me pls)