Maybe your guides are just suggesting a different perspective in order to help you deal with your grief. You can't help the way you feel about the cat and how everything transpired. It was traumatic and not an easy way for the kitty to die, being torn apart in a fight. You did what you could for the poor thing. It's OK to feel bad about the trauma. That's natural. Maybe what your guides are suggesting to you is meant to help you deal with it. It doesn't sound like you should be laying a guilt trip on yourself.