As a tank, the best thing to do is ignore chat in random groups. When you get a group of idiots, you have a couple options. If it's one idiot, kick them. If it's more than one, quietly leave group and reque. For most levels tank ques are near instant. Life is too short to worry about the vocal trolls in random group chat. And make no mistake, the most vocal are either clueless or intentionally eliciting a response. Good players most often like smooth quiet runs, and do not want to waste time bickering in chat.