DPSing as a healer

[Nanahem]

But why ONLY healers? That's what I can't figure out.

Because they are high-demand enough to get away for it. You don't need to tell a bad tank he's a bad tank, the aggro list and dead members will tell them. Get a bad DPS? Just kick him, someone will join in a minute and will be very happy to get half of the duty done.

Now, healers? Keeping everyone at 100% HP is enough for mostly people (healers and non-healers party members). Don't like my playstyle? I'll just quit. Good luck getting a in-progress healer.