I don't see any reason other then if it is so matted that there is no other way. Cats have natural oils and the fur keeps them cool in the summer and warm in the winter. That is why they shed in the usmmer to get rid of the excuse fur or grow more in the winter. Shaving your cat is probably not a good way to get rid of its excess fur; your cat could get skin problems and skin infections and its gives ticks and fleas and easier way to the body. If you want to get rid of excess fur the best thing you could do is brush your cat with a wire brush if it is long hair, or a rubber or wire brush if it is short haired, and brush your cat everday; it will also give your cat love and attention. The only other reason is the mats are so bad the skin is starting to die. If you have a long haired cat and you don't brush it enough then maybe you shouldn't have a long haired cat. I have a ragdoll and if you touch her you are covered in white hair, but I just buy way more tape then usual now. Some cats fur takes so long to grow back. Ever think if you shave it it might never grow back? I know on humans sometimes if you shave a curtain area, it wont grow back. I know first hand on that one and it sucks. Wish it was a different part. LOL