Because people didn’t utilize him correctly, where they would constantly fly and maintain LoS of the hunters, and thus chip damage was done.
People were suppose to “bunny hop” with him, where they fly, traverse, then land. It gives him the movement boost, while keeping him out of LoS. HOWEVER this was the byproduct of the learning curve, like how new Behemoths would stay in one place and eat every bit of damage, even allowing medic to take away 2-3 health bars alone during the match.
I was strongly against passives, because they seemed like simple fixes to complex problems, and the only way to solve the learning curve was through extensive tutorials or an in-game balancer like you’ve always advocated for.