You absolutely did the right thing OP. For me, it's more than just attacking the wrong target that will make me refuse to heal someone. For example, in Titan HM a few weeks ago there was a drg who would go balls to the wall from the second the tank got Titans attention. He would blow all his cooldowns and pull hate, while the WAR struggled to get it back. This was very chaotic, and we wiped. After doing this twice, I told him he needs to wait and let the tank establish hate before going for big burst damage. All he said was "Learn to tank." Granted, the tank wasn't the best geared, but he was trying his best and the DRG was just making his job unnecessarily difficult. Then I warned the drg if he did it again I would just let him die so the tank could get hate that way. Lucky for him he took me seriously, and two tries later two of my friends got their shiny new relic!