I think people may be reading more into this than was meant.

When I was about sixteen, I had a kitten and ran over it. Seeing that cat die, I actually think that its spirit has haunted me. I wasn't afraid of cats before. But now they scare me to death.
Personally I interpret this to mean he was traumatized by running over his cat. No where did he say that he hated the kitten and so chose to run it over for fun because that's what cats deserve. Don't put words into people's mouths.

Oh and I'm not a Clay Aiken fan. I'm not even an "Idol" fan I think it's a dumb show.

I do know that I don't trust PETA though.