Lot of good friends in the UK and the issue is that people from other lands leave those places because of security or economic concerns and when they arrive in the UK(Or France, Germany,etc.) they want it to transform in to the place they left. Not all, but a significant amount do. Which leaves their children not seeing themselves as British or as Pakistani(Nigerian, Indian, etc.). That's when the hate preachers latch on, just like MS13. They target those that don't have a strong sense of belonging and offer that. As part of the deal they push that its the fault of all those other people, the non-believers that your life is so much dog crap. No wads of cash, big house, fancy care. The answer, they believe, is to kill you. Do that and suddenly it will all be better.

Kind of dumbed it down a bit, but that is what is happening. It happens here too, just not as often and usually in a more criminal rather than political context.