So where do you put zero? By this one completely arbitrary decision you can collapse total utility maximization to one of these cases.

It gets far worse when you try to apply it to animals.

As for zero being very high, I've actually heard many times this argument about existence of farm animals, which supposedly suffer so much that it would be better if they didn't exist. It can as easily be applied to wild animals, even though it's far less common to do so.

With animal zero very low, total utility maximization turns us into paperclip maximizer of insects, or whatever is the simplest utility-positive life.