I think then the discussion would be around why only minimizing suffering for humans. If minimizing suffering is a good thing, why is there not also value in minimizing suffering for all beings that can suffer?
Of course that becomes wrong if many humans embrace the idea that minimizing suffering for animals is a good thing. At that point you would also be increasing the humans' "moral/ethical pleasure" in a kind of self fulfilling way. But there's no reason for this to happen except human hubris.