It surely isn't necessarily the case but I've been with a few people, including one of my main crewmates, using BM as a distraction in PvP games.
No namecalling, @sshole or mom insults, but mainly in the form of taunts, sometimes mean, sometimes telling people to delete the game, they suck and the like. When he does it, he is actually calm and focused, not raging, but for him the incessant barrage of taunts is meant to p*ss off the opponents, reducing their concentration, aiming and logical reasoning. I hate when he does that as I try to stay as cordial as possible when I play, but I'm sad to observe that it actually works. After a while I can spot rash decision making, little mistakes and an overall lower level of play. He says that "in a PvP game every tactic is fair game, including psychological warfare". I don't agree it's fair, but it's effective and I'm pretty sure he's not the only one usimg BM for this in the gaming world.