A kitten isn't a mouse or a fly. Dogs and cats have an approximate mentality of a 3 year old (mice don't have reasoning ability). So hurting or killing a pet (something about interacting with humans enhances part of their brains) is the same as hurting or killing a 3 year old child.
Also, torturing animals almost always leads to doing the same to humans.
And yes, hurting a pet hurts the owner. If someone was to hurt my cat (see my profile), I would end their life it at all possible.
"Hurting or killing a pet...is the same as hurting or killing a 3 year old child."
I hope you're joking or at least exaggerating your position. Really.