I love my cats and dogs, but I know they aren’t human.
If someone killed one of them, I would be very upset. I wouldn’t kill someone over it though.
If someone did it to one of my kids, well we would skin them alive and hang them by their entrails.
I don’t think one need distinguish. You are measured by your love and commitment. I would not let the killing of my bunny stand, just because the offender was a human being. And if I were there to STOP the attack, you can best believe I wouldn’t stop, even at evisceration, to protect my little girl (my pet.)
You made a promise and took responsibility and by that you are found either sufficient or wanting. If someone was about to attack and kill your pet and you didn’t stop them (with deadly force, if necessary) you aren’t worth much. But I don’t think that’s what you meant.