Who are you to decide what the tank should or should not be doing? If you're not the tank, that's not your call.
---------- Post added 2010-11-02 at 01:45 PM ----------
Warlocks assuming I'm going to heal their lifetap is the ignorance, not my refusal to do it. If they ask first, I always heal it. This could change in Cata, but probably not.
Also, since when is the warlock's mana bar MY responsibility as the healer? My mana is dedicated to other things first, and anything they get from me is a bonus. Expecting me to keep their mana up is ridiculous. ASKING me to assist is not. See the difference?
The douchebaggery comes from not only engaging in poor behavior, but defending it. You have not changed my opinion, nor will you.