I doubt I'll say anything that has not already been said. Players of all types can be unsociable. It gets noticed more with tanks because they are the focal point of the party. Good tanks and good heals often cover for bad DPS, but DPS generally can't cover if the tank or heals fail. Few notice and fewer care when DPS are unsociable, they're part of the background. So when a tank or healer gets or gives grief, people notice.

Extra pack gets pulled into the party? Eh, just another tab targeting ranged dumb@ss who doesn't look before he hits the next ability.
Similar thoughts for most of the points made in earlier posts.

I don't really care if we get rage for our attitudes from bad DPS and entitled healers. (I like to heal as a break because it is the hands down laziest job in MMOs.)

I don't rage on other players in the lazy roles who pull dumb crap, sometimes mistakes happen. But the actively malicious "gogogo" DPS who make life hard for the new kids and the heals who like to pull extortion tactics on the other members... these I have no time for. Takes me fifteen minutes to wait for the DF cooldown, I can grab a coffee and run a couple FATEs, it takes them longer to wait for another tank.

I have not tanked much in this game, I'm taking the time to level slowly and enjoy all the content, but I've tanked extensively in other MMOs. I love the role, I love being the in your face leader up the front taking the boss on while my sidekicks have to creep around its ass or snipe it from afar. I love levelling with something that doesn't get torn apart by random mobs out in the wilderness.

I'm starting to think other players constantly whine about tanks because they're bored spamming only 2-3 buttons and in need of attention due to choosing to be the support staff.

Now I'm just musing, so I'll leave on that thought, it makes me smile.