Many breeders cut tails in puppies if that is what their breed demands.
Not all do, but many do.
Tails are cut at two days of age in puppies that are in good health.
At that time, their nervous system is not evolved enough to take note of the tail cutting any more than if another puppy steps on a paw to retract it and yelp, maybe.
Cutting tails after the puppy is more neurologically mature is surgery that should be done by a vet.
Tails serve different purposes, from helping balance the dog to a way to communicate how they feel by the way they use them.
When cut that young, dogs grow up fine without that, so it is a toss up if to cut tails or not.
There are some dogs with tails that have continuous problems with injured tails and eventually need amputation when grown, it is a problem in some danes.
Now, ear cropping is done when the puppies are older, it is hard on them, it is really unnecessary, cosmetic surgery.
We have to choose as the breeder or owner of the puppy if we want to go there in the breeds that used to demand cropped ears for a certain look.
We had some dobies in the early 1980’s for obedience and they were cropped by the breeders, no one would sell a puppy that was not going to be cropped, it was not done then and we didn’t want our puppy to go thru that, so for that and other reasons, quit dobies.
At that time, it was not unheard of for a vet to go to a breeders home and crop a litter in their kitchen table.
The cropping was simple, the aftercare not so much.
My guess would be, many of those pit bulls with cropped ears are part of the underworld of dog fighting, where they crop the ears to keep the other dog from having something to hang onto when fighting.
