I still don't have many moral qualms about allowing parents to kill children, but realize that actually legalizing it in our current society would lead to some unintended consequences, due to considerations such as the Schelling point, and killing infants as a gateway to further sociopathic behaviours.

Yeah, that's roughly my stance also.

So maybe a wiser way to reconcile these would be to say that since infants have less blicket than animals, and we don't kill infants, that we also shouldn't kill animals.

I was really hoping someone would come to this conclusion :). I don't agree with it, but it does seem the obvious consistent alternative to my position. Unfortunately, at least if you want to understand your moral position so well that you could build an FAI, you're still not entirely out of the woods - you have to describe a criterion for "ok to destroy" vs "not okay to destroy", ideally one that generalizes to machines and aliens. And "has sufficient amount of blicket" is still probably the best you can do. Certainly it's the best I can do.