I played a tonne of online multiplayer shooters as a teen (Halo, Gears of War, CoD etc) and did my fair share of trash talking between friends and occasionally against strangers in public matches. In saying that the trash talking used between friends and even from what I experienced back then from strangers was never more than insulting each other's skill or at a push calling someone a dick. Most of the time it was stuff similar to gags used on the Purepwnage online series. I dropped off from online multiplayer games along time ago and if I do play online now it's generally without a mic and with the other players muted. When I was starting to play less it was when the Modern warfare games were ruling the online fps games and lots of kids started playing and that's when I started using mics less because it was full of kids using terms as insults that they probably didn't fully grasp.
As for Pewdiepie I watched both the video where he says it and the recent "response" and he definitely should be held accountable for it. As many in here have already said you don't throw out a word like that in the way that he did unless you regularly use it. I find him completely insufferable anyway from what I've seen of him and from watching some of his stuff over the last few days the way he seems to edit his videos seems so brainwashy. It was pretty weird watching them actually in my opinion anyway.