It's unfortunate... But a very good chance to observe failed leftist ideology. Multiculturalism leads to this. You want it to stop? Then quit pushing multiculturalism. This doesn't happen in homogeneous groups. So take the time to let this run it's course; and learn from it. Maybe you can avoid getting a front row seat for a showing much closer to home...
Frankly it is an observation of Nationalism and religious bigotry run amok- which is of course what Trumpsters applaud.
Perfect example of how if you allow Nationalism and Religion to control a country your people will end up leading the pogroms to weed out 'the undesirable' - the Jews, the Polish, the Mexicans, the Japanese, the Catholics, the Muslims, the Christians.....which ever group your Nationalism chooses to be the target.