Maybe it is because they are supporting the wrong side. If italy stops supporting israel there will be no violence. I bet many violent protesters are born in italy. But if italy is supporting a zionist apartheid regime that is killing zivilians in a massive genocide, it is the right and the duty of every citizen to fight this injustice. Some fight with words, others with stones. But the zionist regime is actually dropping bombs on people who can only defend themselves with stones.