It isn't self promoting. I don't tank anymore. I burned out on raiding, and moved on to PvP when I play at all anymore, or else do some heroic 5 mans as a DPS. I used to teach the up and coming tanks on my server, because, frankly, there just weren't enough of us.
The idea with the poetry isn't to feed our own egos, rather to entice those who have the capacity to be good to put in the time and effort to get to that level, because, really, it IS poetry to watch a really good tank when done right.
It's like any RL profession, from a chef to a cabinet maker to a surgeon to a lawyer. When you see a good one and they make it look so effortless, like they were born to the steps of their particular dance, that's what inspires people to follow down that road. And now, DPS'ing, I want as many who can do it to go down that road and be that good, because I don't want to &#(% with the ones who can't move to the rhythm.