Who the hell wants a crappy day like that? Certainly not my wife. Jerks like the ones you describe have put her off of dungeons so much that she wont even run them with guild groups because they have given her PTSD. She came back to the game last month after seeing the movie and we started leveling in Pandaria. I convinced her to run ONE dungeon with me to completely do all the jade forest quests and swore that it would go fine and be no problem and that i only encounter the nicest people in my WOD heroic/mythics. All those people quit to go yell at people in league of legends, i said (a game she also won't play any more because of that exact same behavior).
We zone in with the 3 other people and i kid you not, the very first thing someone said is "wtf is with that old ass pet?" (her favorite cat from way back in vanilla that she had got out for some nostalgia when she started playing again) and then someone started in on her talent choices, while they were running ahead to pull monsters. Didn't even say hello first. Certainly didn't offer any advice to her about what to pick. Well except for one guy who berated her for not having a talent and his friend said "that's a 100 talent dude" and the guy said "lol, still."
Just to put the cherry on a shit sunday, the guy posted meters. She was, of course, last. They laughed at her and said they might as well have four manned it.
So yeah, pretty terrible evening of wow and I can pretty much guarantee that they ruined other people's evenings as well. They don't deserve to talk in the game. Ignoring them won't keep them from making other folks feel terrible and THAT is what is going to kill subscriptions faster.
I would rather take the gamble that this system kills the game than go through one more run with a bunch of insufferable pricks ever again.