Plenty of servers in other games do insist on only English being spoken and I can see why. It's a global language after all, a huge number of people speak it at least at a basic level and it is, for the large part, the language of the internets and internet gaming. And what's to say two people aren't insulting the crap out of each other or any other such trouble and an admin can't understand it? I can see the reasoning behind it. At the same time I'm not fussed either way.
I can see why people get pissed at Russian's though. Considering you run into all their dick moves and then often see them typing stuff in chat afterwards...does make you wonder wtf they are saying sometimes.