This entire post is toxic. It immediately targets Healers as nothing but heal bots. It was started with a strawman argument accusing Healers of not DPSing. You want to know the reason why it happens though? It's because tanks pull wall to wall so that Healers don't get a chance to DPS at all. They're stuck on a mindless loop of spamming a heal every 3 seconds unless they're a WHM that has benediction up so that they can quickly cast an Aero III or something just so they can DPS with a DoT.
If you want Healers to use their full kits. You need to give them an opportunity to do so. Wall to wall pulls are barely even saving any time. In some cases, it's a waste of time and its even worse with a wipe. So, if you want Healers to do DPS, don't pull wall to wall like the idiot tank who wants to stand in AoEs like you are that forces Healers to dedicate even more time to spamming heals. That way you only guarantee Healers don't get a chance to cast any damage spells at all. It's like the stupid tanks who wait until their HP is down to 30% before the activate a cooldown.
However, keeping a tank at 80%+ is a viable strategy. For some classes, you need higher and the reason for that is that's about how much damage the tank buster deals. It's better to keep a tank topped off with smaller heals and avoid the need for the big cd instant cast spells that are for emergencies until when you really need it. That way, the chance of the tank dying to the tank buster drops to 0, even if the tank doesn't pop cds.
For starters, the more you pull, the less likely a Healer is going to be able to DPS because they're too busy keeping an idiot like yourself topped off because you pulled wall to wall instead of a small group. There's a reason why they are divided into small groups of usually 3 mobs and why most Healers only DPS in Raids. It's the only chance they ever get to assuming the tank that refuses to dodge AoEs.