Andrew Stuttaford points to this Guardian article about violent anti-Muslim protests in the Netherlands. I blame the Dutch government. They stifled open, peaceful protest so what did they expect? It found an outlet in anonymous, violent protest.
In the article, a Muslim man is calling for more limits on speech. That is likely to lead to even more violence. The Netherlands is a Western Democracy. The people are used to the idea of using peaceful protests and voting as a way to express themselves. If the government would just get out of the way, that is how most of them would do it.
But leftists (the so-called centre-right government of the Netherlands is still leftist) don't get that. Their view of humanity is that the rabble is an unstable, dangerous beast that must be carefully controlled for its own good. They have this model that passions work higher and higher until they explode into violence like the baiting of a dog before a fight. You keep poking and prodding at it to make it angry enough to fight.
But have you ever seen how a chained-up dog reacts to a stranger? It'll bark and jerk at its chain, trying to get at the newcomer. The dog quickly becomes frustrated and angry. It's hackles come up. The barks get lower pitch and you start hearing growls and snarls. If the stranger stays around for any length of time or does anything the dog considers provocative (and that can be almost anything) the dog goes wild, jerking at its chain and giving every appearance of wanting to tear the stranger to pieces.
But let the dog go. It will run over to the stranger, sniff a little and maybe snuffle and harrumph a bit to let the stranger know not to get out of line. It was the frustration that made the dog angry. Remove the frustration and you remove the anger.
If the government really wants to head off mass violence, they need to avoid frustrating the population. First of all, that means they don't stifle protests. Second, it means that they see the same problem the people do. The Dutch government has given every indication that they think the problem is not Islamic terrorism in the heart of their cities, but the reaction to the terrorism by the victims. That is going to frustrate the hell out of people.