Except it is intended by the game that you DPS as a healer - I've done the newbie-stuff on an alt recently and its basically telling you "Hey, if everyone is well, go and deal some damage!". You get all those fancy DPS-skills to use, not to sit in your hot bar as decorative elements! You're playing far from good when you choose not to make use of your ablities and skills - and no "Dont DPS if you dont feel comfortable" doesnt apply here when someone just flat out says "I wont even try because I dont want to".
I'm sorry I have little sympathy for people not even trying and making runs longer than they have to be... and then snapping and getting all rude when you point out flaws that you really, really shouldnt explain to someone who reached level 60.
As a tank I stop dodging and using cooldowns for healers who dont dps.