No, actually, they took my advice quite seriously. Which is why I bothered giving it to them. They were actually a very nice person, from what I could tell.
Not quite THAT bad, no. Throwing insults around, myself being the victim of a few of these, getting riled up at other people, saying things that he probably would never say to anyone else face-to-face. He'd go all-caps mode.
I won a round against him, and he was at least decent enough to say gg. So we started a conversation, and I said blatantly to him that he was pretty rude, and we then proceeded to talk about ways to calm down when you're too riled up in a multiplayer game.