There is just so much wrong with this that it isnt even funny.
Who is playing the blame game?
The fact is, Tanks Learn Through Group Play How To Tank Effectively, a tank can read all the strats in the world but is likely to fall on his face at LEAST once during a group run. A dps can learn how to play in a group very effectively in a bg. And a smart dps of a tanking class will actually read what their spells are doing and NOT USE A THREAT GENERATING ABILITY IF THEY AREN'T TANKING. There are things we can all point out in each others performance that are not suitable for group play in most circumstances, and this even includes the tank and healing roles.
Don't Fear Mobs
Don't Use High Threat Abilities
Don't Taunt Unless Asked
Don't Berate Fellow Group Members
This all really comes down to two things... Read up on your class and be open to suggestions from other players. You don't have to take those suggestions but remember if people are complaining about it then it is likely a deterrent to the group. The only thing the lfd has done is put those people with short fuses in the drivers seat, and I aint talking about the tank. Tanks are getting hurried and put out of the position where they can just sit back and look at a situation as a new tank. It isn't the heals or the dungeons that keep me from tanking on any of my characters, it is the short tempered, cant read skills, gottagogottagogottago, pulls for you dps. So, yes, it is the fault of the dps that there is a shortage.
And yes, I am looking at it from the dps and healer perspective. If I go tank, it will be for friends only.
As for the whole turn the mob around, if it is a dragon, turn it, if not, I am usually on my way around already and if you are there tanking I get confused.
For the complainers in my groups, the tend to be dps characters, rarely a healer or tank complains about the preformance of another member.
Just face it now... People are rude and the ruder you are in dungeons to group members the less likely they will be to continue in what ever capacity they are trying to fill. If you are rude to a tank or a healer then have to suffer through long wait times... You might just be on everyones ignore list.