I don't think there's a solution to this. In PUGs I consider myself lucky if any of the DPS know how to pull what could remotely be considered respectable damage (ie have even half a clue how to execute a rotation) let alone put forth any effort to prepare themselves for a dungeon.

Instead what we get are people ignoring mechanics, performing their jobs poorly, and blaming healers when things go wrong. Other than running exclusively with friends, there is nothing we can do to stop this selfish and ignorant behavior.

I gotta say though OP, if you are refusing to explain mechanics I don't think that's really helping anyone. If there is a solution, I just don't think that's part of it.