I should perhaps clarify. Killing a newborn baby by horribly mutilating their anus is of course worse than them dying in their sleep or whatever. Blood loss due to having your anus ripped apart is going to be an extremely unpleasant way of dying no matter how cognitively developed you are. But I'm not sure if I see where it being rape becomes that big a deal. The anus is just another body part. The badness of rape is because of the various emotions that sex is associated with, the added sense of violation and whatnot, and I do doubt that newborn babies can really grasp those sorts of concepts.
After all, the article prefaces itself by saying something to the effect of "You think that the ten month old rape was bad? Listen to this!" Why is it worse to rape to death an eight day old than an ten month old? Death is death. Blood loss is arguably worse than blunt force to the abdomen, but's not how they seem to phrase it. They seem to be implying that a crime being more perverse makes it more wrong, and this seems illogical to me. If a person steals my computer because they need money or because they want to masturbate into my CD drive, it causes me the same harm either way.
But no, I don't have kids. I'm only 21. If there is evidence that I do not have access to because of that, then of course I would gladly like to have that evidence so I can revise my theories, but if you mean merely that people with kids would not take such a cavalier attitude towards baby rape, in which case I do not see the purpose in introducing such emotional biases.
A human life is a human life. The interests of a guy who goes on a killing spree or who molests a newborn baby are worth exactly the same as the interests of anyone else. Of course, in general, we cannot satisfy the interests of people who go on killing sprees or who molest newborn babies without dissatisfying far more people. But that doesn't mean we should just kill them off the moment we have a chance. They still have interests, and those should be weighed accordingly by the legal system.