I've been in those dungeons on both those jobs, what everyone was asking of you in every one of those situations is not hard to do, nor should a whm be telling aoe dps not to aoe fighting 3 mobs. I'm trying to figure out from what you've said why you couldn't/wouldn't handle it, idk best I can come up with is not everyone's cut out for tanking.

But it really, really, really looks like there's another side to the story and the people you had these bad experiences with, if they read this, would tell similar bad experiences of a tank that just didn't keep up like most other tanks in those same situations.