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

[KokonoeAiyoko]

Your argument is even worse:"It's not bad tanking, just inferior CD usage!" - Tank that doesn't want to use CDs.
"It's not bad MNK DPS, just inferior positionals!" - MNK that doesn't want to use positionals.
"It's not bad DRG DPS, just inferior combos!" - DRG that doesn't want to use Blood of the Dragon.
"It's not bad SMN DPS, just inferior DoTs!" - SMN that doesn't want to use DoTs.
"It's not bad BLM DPS, just inferior use of fire magic!" - Ice mage.
"It's not bad support, just inferior TP/MP regeneration!" - BRD/MCH that doesn't use songs/turret.

But hey, it's all optional optimization, right?

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.