There's a difference between a medically necessary procedure -necessary as determined by a vet - and one for vanitys sake.
But who gets to decide? There are loads of cases in animal husbandry of doing something "grey" morally for the prevention of a problem which may in fact be marginally or even more so harmful for the animal. If being right is leaving the dog precisely as nature bore it (which is fine if that is your standard) then the following must be wrong all the time.
Dogs - debarking, spaying and neutering, dewclaw removal, tail docking, cropping, disarming, branding
Cats-spaying and neutering, declawing,
Goats, cows, sheep - disbudding, dehorning, castrating, ear tagging, branding
pigs - castration, teeth clipping, tail docking, ear notching
Reality is that we alter animals all the time for vanity's sake, for health reasons, for population control, behavior modification, for safety both for handler and for other animals. It's just what you feel is too far which imo is a permanent aware loss of quality of life or a likely result of lasting uncontrolled pain. The bottom line is that it should be a decision between vet and the animal's owner, not something dictated in a broad brush by a dealer or a rescue unless they do not give up ownership and financial stake of that animal.