The importance of the breeding of the horse and his conditioning are two principle factors of significance in Horse racing.
One can also bring up the ethics of damaging so many two and three year olds by having them race before their bones have developed adequately to protect themselves form life destroying injuries.
The effect of racing on the mind of the race horse needs to be considered.
Purse size and the significant sums of money that can be won if victory is accomplished effect the integrity of the trainers and owners of race horses.