I remember always trying to do damage even back in ARR. Started in 2.3 when that shift was coming into fruit. Healers weren’t expected to do damage but raiders realized how significant it really was and started trying to work to maintain it. Scholar was the better class at doing so by far so it was really them that carried the idea onto other healers. Hell it’s where the idea of main/off healer came from. Back then WHM had better tools for burst healing non-tank classes while Scholar’s main advantage came from most of their actions working in Cleric Stance without any loss, only really needing to swap for shields (which still had issues). The go-to meta in casual content was “Work on DoT uptime first, add in filler once you’re comfortable”.