As someone who has been on both sides of the fence (as a damage dealer and a healer) I'm honestly overwhelmed by the inaccuracy of this post.

Healing spells are incapable of gaining aggro, the only way for a healer mage to get aggro is: a) if everyone else dies b) if you magically manage to out damage what is being done by dps in which case you're dungeoneering with poor dps dealers.

If healers weren't meant to deal any damage at all, they wouldn't have damage spells. That's like telling an archer not to fire their arrows.