90% (made up number) don't speak English. If you try to communicate with them you get trolled in their home language. Frankly they're often obnoxious arrogant and unpleasant.
There are obviously exceptions though, not everyone is like that. But enough of them for me to understand why someone would move to a US server, at least when you get trolled there it's in a language you both understand.
Basically they're the EU equivelant of the Brazilian player base the US people hate with the XOXOXO crap.
I'm from Poland, my english is fluent since I've been working abroad for quite some time. What you're saying is just pure bullsh1t, it's like someone would say that every guy from USA is fatass hamburger lover, every russian is a drunkard and every muslim is dirty and carries some TNT under his shirt to blow up your hometown. Get a clue...
Game is simply amazing and beautiful. Gonna spend next months (years?) playing together with my wife. Enjoying the views, story and just having a blast while fighting everything on my way