What is this new anti dps healer attitude?

[Gallus]

Your first and most important duty is to heal. You are there for that. If there's someone you could've saved and you didn't because you were dpsing you should take the blame. If a tank is not using cooldowns you can't change that, you cannot change others skill level, the only thing you can do is be a better healer yourself. If someone exploded from 100% to 0% in one second even if you were dpsing it's not your fault, but the same moment you are making runs less safe because you want to DPS then you are not being a good healer. Basically, with pugs, only DPS when the boss is harmlessly autoattacking or when handling mechanics that you know will hardly kill anyone.
Personally, I think a great healer is the one that saves runs and makes up for others' mistakes. The moment you let your NIN die from an unavoidable AOE that you knew was coming like 6 or 7 seconds ago, and that NIN was at 60% of their health because they just came from screwing up a mechanic, and you let the NIN die because you go by the "not my fault they failed a mechanic" when you could've saved them provided you casted a heal on them rather than a couple malefics/broils on the boss, then, you are not a good healer.