Yep, screw people like that. I've been lucky enough to only get people who use Clemency and Vercure but that's still infuriating, I'd imagine someone going off on you or anyone else for doing what you did would make the healer enraged as that is what you are supposed to do with 5.0 healers, minimize heals and maximize dps, you can literally go 80 dungeons without using a single afflatus spell as WHM. Leaving was perfectly justified and understandable.