I've noticed this too and this is something that started long before blizzard even announced wow classic. People have become so toxic online now days it's going to kill online gaming. Look at the horizon, there isn't a single decent budget MMO coming anytime soon, if ever. I started online gaming during the days of 300bps modems and what I've seen the online experience erode into since those days is shocking.
People think a blanket of internet anonymity gives them a free pass to displace the personal baggage in their lives. And this isn't a "Europe" or "American" thing. EVERYONE. EVERY COUNTRY. EVERY NATIONALITY has their douche bags. People wanna take a few bad experiences from a certain demographic and then run around lumping that entire demographic into that bucket.
I can tell you right now, I am American and I despise our younger generation more than anyone. Most Americans over the age of 40 do. We've become a self-centered, self-entitled, toxic, miserable country over the last 10 years and most of these kids need to be taken out back and tuned up and given the parenting they never got. Bunch of brats stomping around demanding free shit while a lot of people on this planet have it much much worse. Our millennial generation grew up with more stuff and more benefits than any generation in history yet they act like spoiled narcissistic brats. It's very hard to be tolerant of people like that.