Racing question

after the Grand National festival at Aintree, in which only two horses died, I watched a television question show yesterday morning that asked for opinions on the safety and ethicality of ­national hunt racing.
The proponents, including a veterinary surgeon employed by the racing board, and a former champion jockey and Grand National winner, told us that the sport generates much income, but also informed us that the horses were bred to, and loved to run and jump.

This is what puzzles me. If this is the case, why does a racehorse have to be whipped and initially does not run until the jockey spurs it on, and why, if a horse has unseated the rider and is running freely as a herd animal, will it deny itself the pleasure that we are told it craves of jumping a life-threatening obstacle, and choose to run around the fence on flat ground if possible, as we often see?

Maybe someone in the racing fraternity can enlighten me.

Walter J Allan

Colinton Mains Drive