Eh... we do have to neglect a lot of things, but I don't think I'm being biased in my choice of which to consider. Making it illegal to kill people is a huge net positive to the amount of fun had. And I've never held that other people should be allowed to kill your baby, for precisely that reason: making that legal would significantly reduce the amount of fun you'd have. I'm only arguing that you should be allowed to. So I'm not quite sure what your point is; either you've misread something of mine or, just as likely, I've misread you.

It's also not clear that subtracting a person from the universe reduces the amount of Fun.

Well, this one is certainly more clear, because you can look at how it hurts the people around them, and so on. I'd give very good odds that most murders do reduce the amount of fun.