About the cleric "denying" healing... I think we are talking a situation where the cleric has limited healing magic in him (and there always is a limit) and choosing to distribute his healing "juice" wisely.
Say cleric has 150 points of healing to distribute/day.
Fight 1:
Fighter: I took 20 points of damage
Wizard: I took 5
Rogue: I took 15
Barbarian: I took 50
Cleric: dang, that was rough! Ok line up everyone. I only have 60 hp of healing left folks, be careful ok?
Fight 2:
Fighter: I took 16 points of damage
Wizard: I took 15 this time, sorry
Rogue: I wasn't hit at all ha!
Barbarian: I took 57, it was glorious!
Cleric....
DM: you can hear the orcs coming, better hurry up!
That crazy barbarian is sucking out all the healing of the party. You guys are saying the cleric is a jerk for deciding to limit healing the reckless player's PC to the max. But wouldn't he be a jerk to deny the other players' PCs healing because the reckless one needed all of it? If the cleric has massive amount of healing power, then it doesn't matter so much. But if healing resources are limited, I think healing less the one who's being reckless needlessly is *not* being a jerk.
P.S. of course, if one character took more damage because he was protecting the party from the big bad monster or guarding the rear whatever, that's not the same!