First off, I'm very sorry you had to go through this and I really hope it didn't have too much negative impact on your future life. Speaking from experience, I was only able to cope with my past many years later and I still sometimes struggle with social interaction because early childhood bullying made me extremely insecure.

I don't really know whether school children here are more violent than elsewhere. I honestly don't think so. Bullying is something present in every society, among young boys and among girls during teenage years and especially for the former ones, violence is an essential tool to perform the bullying. Also, I don't think the primary targets of bullying are expats or immigrants. But as you already stated later in your post, you just have to be different: If you end up to be the only Muslim in a group of Christians, you're different. If you be the only Swiss in a group of e.g. Albanians (suprise, that constellation is not uncommon is Swiss primary schools), then you're different. And this is exactly why bullying happens (though I admit it's not really a 'good reason').

Anyway, so what about the teachers? Yes, they often simply don't care. Unlike in the U.S., in Switzerland the school system is only expected to teach the children school stuff, like maths, sports, biology and what not. Social integrity, social behavior and all that stuff is expected to come from the parents. So what happens outside the class room is not something of the teachers business. And if a child comes to a teacher crying because that kid did this and that, many teachers will simply ignore it because 1) they didn't know exactly what happened, 2) especially with fights, they think it's just boys stuff (I mean, fighting is a normal thing boys do, it might be hard to see if a bruise came from a punch in a fight or bullying), 3) they are not there to punish children for bad behavior, that's up to the parents and 4) we already had cases where parents got after the teachers after they tried to solve a conflict because they 'obviously' made an unfair decision towards 'their lovely angel son' who would never harm anyone.

So, long story short: Bullying is a 'normal' thing everywhere, but teachers here, as you already noticed, look away because they are just that: Teachers. They are not parents, not the police, not psychologists or anything. Also, if you go to a teacher saying someone did something, it's definitely Swiss mentality to punish you instead because tattletale (don't know the right word here) is something frowned upon.