I'm by no means anywhere near Coil (didn'T even set foot in Turn 1 yet, though that's largely due to all groups shouting for "exp only" which I don't feel I have even after watching vids) and I can't understand how so many people have problems?
Granted, I'm tanking since Wow Vanilla and I did progress-raid for a year or-so in each of BC and Wotlk (no server-firsts or anything the like, but serious raiding 3x a week with a static if you will), but not yet have I ever been treated badly in this game. Not even once. I've played several 100s of 4 man dungeons and really never had anyone tell me off or harass me. The "worst" I ever got was "pull more mobs". So it's either you're worse than you think, or your behaviour that is leading to these flames (I can't believe I've only met nice people if supposedly so many people treat you like shit...).
I don't want to judge you or anything, nor am I saying you're a liar, but I just can't believe you're being 100% genuine. There has to be a reason for this, or you're exaggerating.
I have seen stuff like that happen in CT, but when it happened the tanks did always do something hilariously stupid (thats of course NOT a reason to treat someone badly, but I've seen it happen at least).
@ the last posting above: While I agree wiping 5 times is not exactly something that lets you get regarded as a good tank, I have to concur with "learning the dungeon". Unless we're talking high-end content I don't see why a tank would be obligated to educate himself before joining a dungeon. Now, I myself do it, just because it makes me feel more confident and as a tank I think that it's something thats needed to fullfill your role to the fullest. However, most DPS don't bother learning content, so why should a tank need to?
And if you're not okay with spending time with new people in a dungeon then go with your FC, it's as easy as that. Maybe I'm a bit too lenient, but if the group is nice (as in chatting friendly) I don't mind the timer as much. For example I had a WP group earlier with 2 BLM at 2.6k life and a healer with 3 life. We wiped like 3 or 4 times and the dungeon took us over an hour. It was still more fun than most runs that take 15 minutes, since you felt like you accomplished something and helped other people out a lot. That stupid rushing of dungeons is getting on my nerves anyway. I do it with my FC to farm tomes, but if I queue up for random people I don't expect them to be l33t-rush0rZ pros....