Its a tough question. Unfortunately, we have a huge overpopulation problem because there are a lot of irresponsible and/or clueless people out there breeding herds of horses that no one wants. Maybe they are breeding hundreds to find that one champion. Maybe they are just too lazy to geld their colts. Whatever the reasons, the bitter fact is that we are the ones supplying the slaughter industry.
A horse, or a dog, or a cat may not be a human child, but in my mind, its pretty **** close. If you buy or breed anything, it is your responsibility to see that creature gets the necessities, medical care, and training it needs to be a functioning domestic animal. If you cannot provide these things, its your responsibility to find someone who can.
So I guess the solution is to stop breeding so **** much. But yeah, try telling that to millions of horse people.