My understanding is that ear docking, tail cropping, etc. began as a safety thing for the breed - so that when they were out hunting, the tail/ears would not get caught on anything or be grabbed by the prey, injuring the dog. Those were later incorporated into the breed standard. But I agree with you - I don't know why anyone would do that if they weren't using the dog for hunting or for show.
I've heard this too, and in the states where many breed of working (and non working) dog are routinely tail docked, it's still given as an excuse.
Of course, it's sort of a non starter, because yes, cutting off a body part means you'll never injure it. The same argument could be made for little toes. We can live without them, and it sure hurts when we smash them against a coffee table leg, so why not cut the suckers off?
But there are breeds of dog that work cattle and sheep--border collies and kelpies, for instance--that are not routinely docked and where their breed standard (in the places where these breeds are bred for show as well as work) does not call for docking. Actually, Australian cattle dogs are not supposed to be docked for the show ring either, but nearly every one you see in ranch country out here is. I believe they leave the tails on in Australia, though, and they seem to do just fine there.
Aside from the pain of the procedure (which is performed on young pups without anesthetic), an issue some veterinarians and animal welfare advocates have with docking is a concern that it might increase the likelihood of knee and lower back injuries. Dogs actually use their tails, not only for communication, but for balance while making sharp turns. Some agility handlers even obtain Aussie shepherds from breeders who leave the tails on for this reason. But there is not a preponderance of data either way here. I do notice that tail-less dogs tend to use a different weave pole technique than similar-sized dogs with tails.
https://www.avma.org/KB/Resources/F...sked-questions-about-canine-tail-docking.aspx
I think the largest reason many breeds are tail docked and ear cropped these days is to create a uniform appearance when genetics does not oblige. Some aussies and rotties are natural bob tails, but it's not possible to breed reliably for this trait, as repeatedly breeding natural bobs to one another will result in some pups with a tail that is so short that the end of the spinal cord is exposed.
And ears that are in between pricked an lopped come in a variety of sets and shapes, and they tend to result from the actions of multiple genes, some dominant, some recessive, and some incompletely dominant. Again, it's impossible to breed two dogs with "perfect tulip shaped ears" and get a litter where all, or even most of the pups have them.
Then there is the doberman issue, where the dog's natural ear is floppy, but the breed's creator wanted a more fierce looking dog with pricked ears. Hence the tradition of cropping and taping them. Doberman pincers with natural ears really do look different--softer and more approachable. Their reputation would probably be improved if their ears were left that way.
And don't even get me started about "battle cropping" bully breed ears with a razor blade. We all know why that is done, and it's horrible.
From this, you can probably tell I'm not in agreement with the American Kennel Club re breed standards, and I'm skeptical over whether or not working dogs are really at such risk of tail injuries that cutting the whole thing off up front is the best approach.
But I do think there's a difference between gently taping an ear that won't stand up when the other does (in a dog) or sticks out at the wrong angle (in a human or dog) and actually cutting into someone to correct what is, at worst, a mild difference in appearance. One is painless and risk free (if done with a doctor or vet's supervision), the other isn't. My mom tells me they taped my ears in the hospital when I was a baby, and it really wasn't a big deal. And for whatever reason, my ears don't look like my dad's, which means short or pulled-back hair styles are an option for me