It might upset some parties, but at the start of the dungeon, lay it out front if you don't think you can handle a speed run, or if you think you're confident you can. Communicate with your tank. He needs you just as much as the party needs him. If he doesn't communicate back, or becomes stuck on stupid, then it's his fault if/when party wipes. The rudeness you've been through, OP, is why I personally detest speedrunners, and speed running in general.