Yeah, I often find that tanks like to blame the healers. I play a bit of everything, but I've definitely noticed that tanks tend to either be undergeared or overgeared. However, both cases tend to expect the party to be overgearred and high aoe dps. Of course, when things go wrong, "Oh, I guess the healer is undergeared and can't do normal pulls." Including when it was completely the tank's fault. (Had three tanks that didn't grab aggro up until he died-I personally refused to heal until they had at least basic aggro on the enemies (aka: at least an overpower or flash or circle of scorn). Had several tanks now that a SINGLE NON-CRIT UNBUFFED Cure took aggro on ALL the enemies from the tank except MAYBE one. Maybe. Obviously, all of them blamed me for being undergeared, a newb healer, and a worthless ____.)
I've seen this both as a healer and as a DPS. That isn't to say that I'm spotless as a tank-if I get hostility from the party, I will match it more often than not. This could include stealthing essentially the entire dungeon-I've done this in Brayflox before and needless to say, party wasn't happy. If the people that wanted to insult me don't like it, tough. I can wait for them to catch up.
Thing is, while I've also seen healers that blame the tanks really fast. And usually these healers are the ones pulling mobs that the tank then has to pull off the healer, who aren't healing, or who are just plain barely geared for the dungeon. You can tell that they aren't healing usually by cleric stance and the fact that when the tank dies, only one enemy aggros the healer (sometimes none).
Generally I see it from the tanks more often. I might be slightly biased seeing as how I'm a healer, and thus I'll see more tanks, but... Just what I've seen. Now, I've also seen some healers blame the other healers as well as Tanks blaming the other tank.
But I've seen healers get very upset because of their party harassing them for being "poor healers" despite it often not being the healer's fault. I think I can honestly call it harassment at that point. And needless to say, that doesn't help with having healers. On top of that, because of the tank favoritism right now, many players are jumping on the tanking bandwagon. Most of these players are bad at their class but won't admit it and instead blame the party, especially healers, which makes things worse. I mean, I'll admit that I'm a horrible DPS. I'm a good healer, but I'm only an ok tank (well, I've had a lot of people say that I'm a good tank, but at the same time, I know I'm nowhere near where I should be).