The amount of drama here is silly lol.

People who want to push their class to the limits, run with healers who like DPSing.

People who want a more relaxed healing style, run with those who don't mind.

If either of you are yelling at each other on how to do a job, you're both jerks. Of course people are going to be "selfish," this is something people do for fun. You're very much welcome to ask your healer to deal damage, but if it makes the game less fun for them, it shouldn't be a big deal if they don't want to. As long as you're not wiping, I don't see how any of this matters.