This is sadly a by product of the whole "tank decides the pace of the run and tank decides if we do a EXP run or a SPEEDRUN". Players are turning alot of the choices that should have been WE into a I (for the tank), because of this we expect alot more from tanks then other rolls. This harms tanks, because this put unnecessary pressure on them, tanks are often required to know the tactics, compared to the healers and dps. Afcourse there are alot of tanks who take advantage of this and become "DA BOSS" they act like selfish pricks who dont care about their fellow players and when things dont go their way, they pull a hissy fit and blackmail their fellow players with leaving a dungeon (so they have to wait a long time for a new tank).

As a tank, healer and dps, I have seen both the ups and downs of being a tank. OP I think there is nothing you can do, you explained and they did not like it, its best to deal with it and move on.