Why does Sage punish you for using your healing spells?

[HyoMinPark]

Correct me if I'm wrong but their generation is only a dps loss if you were to run out of mana because of generating them otherwise they're dps neutral.
2 targets being a dps gain.

But just generating them is the same as simply using a regular GCD except it costs you more mana which isn't a loss until you run out which shouldn't happen unless a lot of people are dying.

Edit: I think I know why it's a dps loss now gunna recheck the posts later.

Toxicon is a DPS loss because you sacrifice a GCD to cast Eukrasian Diagnosis over Dosis III, and a Toxicon isn’t potent enough to make up the lost Dosis III cast. It is only DPS neutral if there is downtime within a fight for you to cast E.Diagnosis while a boss is untargetable.