Considering the father never actually hits him and the woman is laughing, I'd say no child was hurt. Plus, I'd suspect if the father was abusive, the cat wouldn't be standing. (As abusive people tend not to have any empathy for animals.)

However, that's an awesome cat!

awww, kitty, it's the thought that counts!

Consider instead how they discovered that this cat was protective of the child...

Possibly. Also stressing the cat out to get a "cute" video is borderline behaviour.

Our Shepard was very protective of my mom, and it didn't take beating her to discover that. Well, fake beating maybe. People horse around but animals don't always understand that.

My friends have a dog who hates it when he sees two people hugging and will very rudely interrupt you. The same dog will also "protect" his human when we pretend to beat her up. But in his case, I assume he understands we're playing around because as soon as we stop "hitting" her, he goes back to licking, wagging, and overall drooling he does oh so well. My Shepard, well, let's just say I know from personal experience that she could tell the difference.

I've grown up with protective animals, aka, Shepards, all my life. I expect this from my dog, but from a cat, well, that's a cuteness +1 achievement.

This I can agree with. Although, I think it's more unintentional cruelness than borderline behaviour.

Why u no play piano yet?

Cat defends little girl from dog attack has been added as a related post - related requested by braschlosan on that post.