The myth of the century. I'm not super sure about the answer to that but I'll try to see if I can come up with an okay answer.
I think the issue comes down to us being more sensitive as a whole, largely outside of the internet. And some of that sensitivity is bleeding into the internet where people are expecting it to be like the real world when it really isn't. This is due to, in my opinion, relativity in terms of how difficult those people's lives have been. I'm not gonna stand here and brag that I've had a hard life. Heck, I'd argue that if you compared me to everyone on the planet, I'd be part of the group whose lives were the easiest. But I refuse to believe that people who get ACTUALLY angry over those kinds of things have ever had to deal with any real problems with their lives. Its what being sheltered does to people and, although this is not really an issue in the society of the EU, a lot of the "institutions" in the US actually propagate this sheltering. By institutions, I mean education, pop culture and a lot of the social media that is used there. I won't get too deep into it as there's already pages upon pages of content explaining this tangent that I went on but basically, you will only be accepted within those 3 places if you are on the left side of the political spectrum. It is even worse for black people as if you're black, people will fucking mob you if you ever have right wing views as if you aren't an "actual" black person. Its not the discrimination of a "my" type of thinking that is the problem, as I am arguably leaning to the left as I agree with more of their policies and whatnot. But rather the fact that we are cutting down on people who think differently and we discourage it. That's fucking retarded. All of this, leads to people being sheltered from not only actual problems, but DIFFERING OPINIONS. They live through a large portion of their life unchallenged which makes them go crazy when they think that their views are being questioned, even if the whole discussion has nothing to do with them.
I get the feeling that in the EU, people don't really give a shit about anything and are just concerned with working but that might JUST be a German thing. Not sure.
Keep in mind that a lot of the anger online isn't actually real. The whole anonymity of the internet with these usernames and whatnot sort of removes the personal connection between the person you are portraying yourself to be and actually yourself. Its overblown and a lot of the times its just people trolling so it could just be people looking for opportunities to annoy others.