Why not keep it to yourself or your friends though ?
Like what's the need in directly calling out some random for doing poorly other than to male yourself feel better at their expense. Being in a raid with friends and saying your back hurts from carrying people is different to randomly ragging on some random in Crucible because he's having a rough match.
Not sure with what shooting digital people in a game has to do with making real people feel shit for having a rough game.
Ever since 2008, no one talks in game chat anyway. Everyone is in a party now, myself included. So nowadays, all trash talk is with my friends and clanmates. Destiny game chat is a ghost town, plus the audio quality is horrible too. The closest thing to a random player is someone we pull from LFG. We still rag on one another, but leave the LFG player out of our shenanigans and bullshit.
Talking to random players on Xbox Live in 2006/2007, before party chat, was mostly a fun experience. Anyone who was a serious jerk, got muted immediately. But most people were (and still are) decent.
Gears 1, a game with huge muscular men and lizard monsters, shooting the fuck outta each other with chainsaw guns, definitely was an environment that fostered shit talking. It was part of the game. It added to the rough and gritty feel of the over all experience. It was bloody, gory, dirty adrenaline rush of a game. So trash talking was just inevitable. It catered to a certain mindset and specific type of player.
Those who played Gears, particularly Gears 1, know exactly what I'm talking about. But game chat is essentially dead now, at least in games that I play.