Again, the reason healers get more attention on this issue is because nobody out there tried to defend auto-attacking dps and tanks as acceptable play. However, many healers try to claim that dps is outside of their scope and that doing nothing when everyone's topped off is acceptable.
Again, I can't fix lazy people, and they will continue to put forth minimal effort. I can, however, fix the misconception that dps isn't part of a healers job they don't have to do it. That's what the op addressed.
Furthermore, if some healers continue to defend DPS being outside of their scope, how do we distinguish between them and the genuinely lazy players who just want a carry? If we can get the healer community who actually cares on the same page (If I am convinced of anything about the non-DPS camp, they very much do care about the game and about the role), we can be much more confident that when we need to kick mostly-afk players that they were actually being lazy and inconsiderate and they weren't just misguided.
Both sides frequently try to claim the moral high ground, being tolerant of non dps healers on one hand, and trying to increase the speed the run for the other players on the other. In my experience, it's far better to be tolerant and patient when in game, but the forums are for discussion of gameplay so I feel it merits attention and that this is the appropriate place for it.
However, I also strongly feel that much like not everyone on the internet can be forced to not be lazy, there will always be people on the internet who are intolerant of different playstyles. I will always defend their right to vote dismiss healers who are underperforming (even though I wouldn't advocate for it directly). It's been proven multiple times that DPS is part of a healer's toolkit, helps mitigation, and contributes to completion of objectives, so anyone choosing not to puts themselves on dubious ground. I basically just feel people who deliberately don't DPS should just be prepared for that, it's only fair.