The thing is, nobody knows if you are correct. And I understand now, and that is why I accepted your answer.

I don't know why cats attack feet, but maybe somebody else knows.

This is just an idea, but I don't get a ask the next question because you can only answer a question and get to ask a question once, but maybe cats attack feet, beacause some outdoor cats hunt mice or rats, and sometimes even attack things that move. My cats are outdoor, and they pounce on butterflys, and other bugs that are moving. Sometimes, they even attack their own tails! This is just an idea though. I am not sure.