Declawing a cat; why is it unlawful?

It is a surgical procedure which of course is painful but done under anesthesia as is all surgery. Neutering a cat is also painful but done with great enthusiasm. Is there a difference? My cats claws were removed by Lazer which is not as pervasive. She is a very happy cat. I believe that a cat that goes outdoors needs to fend for itself so of course claws are required. But in a house? ? What cat needs to defend themselves in a house? Any cat owner that has been scratched will attest to the fact that blood poisoning to the human is a very real factor. A cat will recover from surgical removal of its front claws the same as it would from any other surgery.