I propose that the practice of whipping horses in the ‘sport’ of horse racing has the exact same root thought behind it as that of the practice of whipping slaves in the 19th century:
That, in order for the creature (which was held to be of a much lower order than the one of the human holding the whip!) to work harder or perform better (or simply just to better entertain!), it was perfectly ok to beat them.
Akin to this belief was the idea that the creature could feel no pain (not as a human would understand such pain) associated with this or that the pain felt was ‘necessary’, minor in nature and reasonable to inflict. People did this while believing that their ability to think and behave in a ‘civilised’ manner to others like themselves gave them a superiority over the animal/slave that their ownership of them demonstrated and hence instilled in them the right to act in the way they did/do.
Most of humanity saw the cruelty of such actions inflicted upon the slaves to human beings a long time ago – it’s past time the racing officials caught up. Especially if, as some have found evidence of, it does not make horses actually run any faster.