I don’t think there can be blanket rules that relate general crimes to general punishments. There are obvious differences between humans and animals, but the HUMAN that would torture an animal probably needs help and should be locked away and I think people who want to take the time to sue over that would have a case. But it’s for a market to decide through private law on an case by case basis
First off, I don’t know how you can say that “most libertarians” think murder can be punished with capital punishment.
Well, some libertarians here think they can force a woman to carry something in her body for 9 months and it’s not up to her to decide if she has choice to decide if she wants to or not. They also think that abortion should be punished.
Second, the cases don’t seem completely equivalent to you, based on what you said earlier - that you’d feel more compassion for the adult dog than the 3-month-old baby.
Compassion is subjective.
Third, and most importantly, morality and rights are inherently human concepts and therefore only apply to humans. I don’t see why it has to be any more complicated than that.
Human concepts or living concepts? Human concepts or philosophical concepts? Not all humans have a shared sense of morality and rights, and I can see that animals do have a sense of morality and respect for one another.
So why don’t you assasinate farmers and scientists?
Those in charge of factory farms and the people who work there who have no sense of respect for the animal they are killing deserve it (to an extent). I can see a difference in someone understanding what they are doing, realize it’s living, and killing it out of respect for continuance (“Life lives on life.” - Joseph Campbell), but not those who pump the animals with hormones, steriods, and antibiotics where their lives are set to a 6 by 4 foot cage in disease filled conditions and they get beat by the employees for the hell of it. The ones who take baby pigs and slam them on the ground by their back legs cracking the back of their skull to kill them - an actual practice by one pork company. Those people? Yeah, they deserve maybe even the same treatment.
By your own defining of “unalienable rights,” babies cannot have such rights because they can neither affirm nor deny such rights. To ask whether such rights can be disputed is a senseless question. On the other hand, a creature with “unalienable rights” can have those rights affirmed or denied. It is the affirmation of such rights, the actual action whereby such rights are granted legitimacy, that brands them as unalienable. It involves certain courses of action being taken by various individuals, and does not rely on mere logical argument or presupposition, which may have no actual effect in regulating the actions of men.