I’d look at why it’s the National where a lot of horses get killed/put down etc. Is it more noticeable because the Grand National is hyped up and full of publicity? (Do excuse me i’m not a fan of horse racing so wouldn’t know if a lot of horses are put down due to the race all year round – not just the National as its a difficult course)
If it’s due to the course… they should make it safer. I’m aware they have in the past but if horses are still dying then something’s not right.
Is it the attraction of money? Are horse trainers/owners putting horses not geared up to jump the course in the race because of the prize fund at stake.
I believe that horses are bred to race/jump and it’s a sport which has a place in modern culture. The injuries to horses is unncecesary if at all avoidable.