In the case of Age of Conan, one player made a guide for Priests of Mitra, a powerful healing class. In that guide, he treated the issue of PoMs doing damage with the simple words 'You don't.' This wasn't all he said, but it was enough to cause a firestorm, particularly when one of the visiting moderators saw fit to sticky the post - which was seen as endorsing a 'you're just healbots' mentality.
It seems to be a particular curse of support-type classes that everyone you group with has a better idea of what you should be doing than you do yourself. We'd like to know, from those who've played such characters: have you ever been told to 'just heal'? Do you care whether you can do DPS or not? Would you willingly give up all offensive abilities to help a team survive better? Or, in a barbarous world like Hyboria, should everyone be dangerous in combat?