Are healers lazy or do some really live by "I only heal"?

[Elamys]

If it was intended for you to only heal, healers wouldn't get new offensive spells in the expansion afterall, right?

Healers get offensive abilities so that they can level through the game. Not so they can take up a DPS role in a dungeon - that's a side benefit.

This is actually the only MMO I've played where healers are, for some reason, expected to DPS. If the group is killing things in a timely manner, don't worry about it.