The analogy doesn't work because horses can't recover from a broken leg, they would be put to sleep if they were in a field and did it. It's not about expense or lack of caring, just reality. The National is a bit of a red herring these days, Cheltenham kills more horses and Horse Death Watch shows it's a regular thing at a much lower level
All that said I used to be a fan of racing, particularly National Hunt. My dad and grandad were massive lovers and I was brought up alongside the voices of Brough Scott, John Oaksey, Richard Lindley etc every Saturday. I went to Cheltenham every year for 20+years and Uttoxeter which is only 15 mins up the road. I have even won the Cheltenham tipster competition on here.
Then 4/5 years ago I stopped eating mammals and thought racing was inconsistent with that life choice. The fundamental argument is similar - without it they wouldn't be born.
Like mammal eating I wouldn't want it banned and wouldn't preach to anyone, it's just not for me anymore