You also realize that I'm talking about times where if you pulled that many trash then the healer wouldn't have time to be DPSing?
Or do all healers pump out massive HPS 100% of the time so get to freely DPS?
I'm not against healers DPSing. I think it's fine.
It's just that, a lot of healers (Mostly Savage Raid geared ones

) make runs last way longer by trying to push their DPS on trash instead of actually facilitating the Tank to pull more trash packs and at worse, cause wipes because they were too busy being in the middle of a Holy cast to actually save the Tank.
If you're doing content where the Tank can pull wall to wall while the Healer is spamming out DPS heavily, sure, go ahead and do it. But it's not all content that allows that and when it is, it's often content that hard blocks actual mass pulling with roadblocks so you're only got like 1-2 packs you can get... With Tanks only having 1 CD that can let them ignore damage for a period of time and heck, Hallowed Ground ideally will only be able to be used ONCE in an entire dungeon, since it shouldn't last much more than its 7 minute CD.
But often, it's not the case. In my experience anyway. The healer won't let mass pulls happen. They instead want to just push out ST nukes on single packs and even then it can be dicey for the Tank always questioning "Will I actually get healed? Or am I gonna need to use Clemency/Inner Beast spam?" this is where the "Pathetic" healer damage comes from. By the fact that they just want to ST nuke (To say nothing of the fact that this also happens in Roulettes that use content below the level that healers get AoE's) instead of thinking "Maybe if I made the tank feel like he can actually take more packs, he'll do so and then the DPS will melt everything down"
Healer ST spam will not ever make a dent compared to DPS vs mass packs but many healers think otherwise.