Same concept applies to healers when they say they can't/won't heal stupid. Sure, on one hand you can say that if a DPS or healer wants to pull, then they should queue as a tank. On the other hand you can say the tanks should just suck it up and do their job, and grab the aggro off of the other party members. No matter what, you get tension all because one person decided that the pace isn't to the their liking. This isn't a mechanical issue, or an issue of time; it is only a matter of etiquette, and a player doing something outside what their role requires to attempt to shave off a few minutes to the run isn't thinking about etiquette. They're not trying to speed things up for everyone else's benefit; just their own.

Unfortunately, speeding ahead still requires the cooperation from the other members of the party, or all you're doing is taking unnecessary damage. If everyone shoots ahead of the healer and the tank dies before the healer can even get into range; don't blame that healer. The entire group just effed up. DPS intentionally grabs agro and dies, once again, the group just screwed up. Being a bitter arsehat because someone stepped on your toes is not part of any job requirement, that is for sure.

All that said, if you want to pull and set the pace for the dungeon, play a effin tank.