1 you can actually tell someone from the EU to do something or not do something.
2 you can actually discuss strategy and picks with someone from EU
3 players type in cyrillic even when they are the only ones in the game that understands it.
4 you are playing on our servers on the EU comprised of multiple nations that agreed to speak English commonly between each other.
5 it's a team game that requires strategy, you trying to point out that it's not needed further emphasizes your disdain for cooperation.
6 there is no right to speak any language apart from English if you are not a with 5 people. It will always be detrimental to speak non-intelligible languages that are spoken by 4 or less players in a team.