I didn't get very far into the programme but was struck by Claire Fox's implicit (and I thought irrational) angle that animals didn't really matter morally because they aren't (in our sense of the phrase) moral beings. I've heard her make this point more explicitly before and it's a quite common view amongst those who don't care much for non-human life. It brings to mind Bentham's famous phrase: 'The question is not, Can they reason? nor, Can they talk? but, Can they suffer?' It seems to be a way of conveniently ignoring the relevant characteristic of sentient animals so as to argue your case on the grounds of an irrelevant one.
This is the reasoning that would justify post birth killing effectively? A child of two isn't moral so we could just kill it. Same for mental disabilities.
I posted a thread on Ethics and Free thought this morning with an interview with Bart Schultz on his book on utilitarian philosophers, and I think your post highlights that the Felicific Calculus is a concept already loaded with the idea of the capability of suffering being the guide to what should be considered. Despite the seeming coldness of having a calculus, and the naming of it after Happiness, it's much more about avoiding suffering and protecting those who do not have 'normal' input to society.
As I said earlier, I am very much in agreement with you that these views are scary, but I'm not sure that that's because they are irrational. If anything they seem 'too rational', in that it doesn't show empathy.
