Opponents of devocalization
In strong opposition to devocalization of dogs, especially guard and similar canines, are individual police officers and their professional associations. For them, the reason is not necessarily moral or based on humane considerations — though from case to case it could be — but rather their concern is rooted in self-defense. Sadly, though not by nature but rather because of training, some dogs are vicious. A police officer responding to, say, a domestic violence call has no idea what awaits him when the door opens. If a dog is barking, the responder knows to be careful. If behind that door there is a non-barking, but vicious, dog, the responder is in trouble.
Proponents of devocalization
American Veterinary Medical Association
Sadly, as the following document from the American Veterinary Medical Association’s website makes painfully clear, the AVMA does not categorically oppose devocalization. Note the highlighted words in the PDF HERE.