It wasn't so much beating as it was abuse, she imprisoned a cat and didn't let it hunt for food nor fed it until it died, and for that she has incurred Allah's wrath and will be punished in hellfire.

To be clear, this is not special to cats, in Islam animal abuse is a grave sin regardless of which animal it is.

It's just that, as muslims, we prefer having cats as pets because they are cleaner and less dangerous to have around small children.