I don't see it as my place to argue with another player over what they do and do not want to do. I simply mark them down on my do not group list if it is a greivance so bad as to warrant it or a significant playstyle clash. If you run into a cleric that refuses to heal and it bothers you, just make sure to avoid them in the future. If you are leading the group be clear as to your expectations before inviting someone to group and if they won't meet it, politely decline them and find a replacement that will. That goes for any class, any group, any quest.
If your LFM's take forever to fill, then consider a hireling and asking yourself and your group mates to BYOH and be self sufficient - with group tactics and careful play, being self sufficient does not have to be expensive. It drives me nuts to run on my cleric with groups where no one has even heard of heavy fortification or curse removal/lesser restoration pots. I don't mind decursing, but if you have a curse that prevents healing and I'm on cooldown, you'll die before I can get to you - especially if you are squishy! Being prepared to take care of yourself to some extent is expected - and if you can't, the healers will very quickly pick up on it and avoid you like the plague. If you are incapable of taking care of yourself, consider this: I once had a barbarian hand me 10 raise scrolls and a stack of heal scrolls, saying only that I would need them. He at least knew his limitations and tried to be proactive instead of just assuming the healer would be able to 100% watch him.