I have seen many healers do this and it baffles me. I have also seen Many a healer use cure non-stop and ignore the Free cure 2 where it would've benefited them more. I have also seen off-healers SPAM the shit out of cure 2 and cure 3 and then beg for a ballad from the Bard. If you can't conserve your MP better imo, You don't deserve ballad at all. I play with a hardcore Bard who feels the same way, so maybe he has rubbed off on me a bit, but I generally don't have MP issues, even in turn 4 of the coil unless I have to spam heal the Tank *which is understandable*.

Generally speaking, you will get better and if they said you suck well, just take it for what it is and say "I can do better, I will do better" and get better. You can do it, because you know you can. Don't worry about the little morons that blame everything on everyone else. Just do your job and handle it well.