I saw this video a couple of days back, it's a funny video really and just chalked it up as a YouTube spoof. If it is real however, the cat has some problems and no-one is going to take it on!
I can't say she's a horrible woman because some cats really are troublesome. I have met quite a few of them. Cats like any other animal have different temperaments and dispositions. But i don't condone hitting an animal because it's cruel.
She shouldn't be so aggressive with her cat, it's probably the reason why her is pet biting her. She should use a water bottle to spray the cat with, as punishment for bad behavior. Slapping the cat like that probably made it angry, and it's retaliating due to revenge based purposes. Notice how it only attacks the hand she's using to hit the cat.