If a run's going smoothly and we're moving along without noticeably long pauses, then I'm not going to care if the healer is dpsing or not. The dps are obviously doing their jobs. If someone in that situation was harping on dps and was typing more than fighting, they're probably the one I'd get annoyed with. A dungeon really isn't the time or place for extensive instruction. I've seen some mentors try to do that when the rest of us are just trying to get through the run, so there are some mentors who do need to pick their timing better.