Why do people dock Rottweiler tails?

Rottweiler was always known as a working breed, at the time this breed was developed to prevent their tails from being grabbed by assailants and to prevent problems which a dog could have pulling the carts (such as the tail getting caught in wheels of the carts) people docked the tail of their Rottweilers. 

Nowdays even though in some countries of Uni

ted States of America and in some parts of the world, Rottweiler isn't known as a working breed but more as a guardian dog, people still dock rottweiler's tails for tradition and aesthetic reasons... 

Since tail docking is done at such a young age (1-3 days), they feel little to no pain because the nerve endings are still undeveloped...

Rottweiler's Tail Standard

A Rottweiler's natural tail is carried hanging while at rest, and often over the back when excited. It normally has a slight curve.

A Rottweiler does not hold it's tail in a stiff position sticking straight out from the body, but it can be captured appearing to stick straight out by a camera, with the picture taken at exactly the right moment, as the tail wags back an forth