They are more RP, even if not in RP servers. We in EU tend to be more boring in terms of Lore and mostly care about numbers, numbers, numbers. It might be a matter of a language barrier since if you don't get the Lore, how can you follow it. But, I don't really think it's that, I think the people are different in that regard culturally.
I have experience in an FPS game that had Americans being more about having fun in it (and showing off in creative ways), while Europeans tried to be mostly about pwning.