Healers that don't want to DPS are like DPSes who refuse to move out of AoEs.

[Taika]

Like most "Pro Healer DPS mandatory or else you're garbage" arguments, it leads to poor comparisons that fail to be a proper equivalent to actual Healer DPS. Guess what? There isn't a equivalent to it that currently exists in this game, hence the drama regarding this, so you cannot compare it with any of the things you've mentioned because those comparisons are directly doing the main purpose (emphasis on main) of the job whereas healer's main purpose is to heal and buff.

How is the "main purpose" of a job defined? By their role name? If so, a BRD's role is defined as DPS in the game. Are they still expected to sing, because that's not DPS?

Your argument is not logical and you still haven't presented any actual arguments for why should healers be expected to only heal. Is there anything else to it apart from the role name or the assumed developers' intention, neither of which have anything to do with how the game actually works and thus should not have any standing in this discussion?