It's a quick buck (BIG bucks) for vets that do this mutilation. Easy for them to do, and excruciating for the cats that go through it. Cats are very stoic by nature, and hide pain very well. I've heard too many horror stories about what the cats wake up to. And declawing does not assure that a cat will always be kept inside. I've rescued several cats ( one badly injured from no defense except teeth) and the others near death from starvation. Plus too many people feel a cat should go outside regardless of if they're declawed, or not.
This lovely cat (below) was living behind a nursing home/hospital for many months. He was petrified at any noise, and nurses would feed him, but he'd wait until nobody was around before he'd come and eat. His tail got ripped off by a car, or animal, and when I trapped him (after 4 trips totaling an hour each trip), I found out when I got him home that he was declawed. I set him up in a cage, and checked his red 7" stump that was very painful looking. I gently wrapped his stump in aloe soaked gauze, and gave him lots of love and antibiotics. He went into the vets on the following Monday for amputation, and eventually went to live with his sponsors Jan & Doug, and their cats after a six month quarantine. If it was Summer, Woody probbly would have died from maggots infesting his stump. Wonderful gentle cat thrown out like trash. I did contact area animal control, and shelters to see if anyone had reported him missing...nope. Woody lives a life of luxury now where he's adored and I see him all the time.

I'd find a new vet also.