I'm just going to reply to the most recent post, because honestly I'm not in the mood to tackle the rest.
A horse that has good conformation (actually, great conformation), a good mind, no genetic diseases that it could pass on to its offspring, is in healthy shape and physically able to reproduce without straining itself, has something desirable to add to the market, does not add to a niche that is already overpopulated, is owned by people who are financially able and educated enough to support it and its offspring, is registered, has good bloodlines, has proven itself in the show ring, has in fact won awards in said show ring (and not just at the 4H level....we're talking the real deal), etc.
Yes, quality horses are slightly overpopulated. Read the certain niches being filled and surplus horses--mainly in the halter industry and TB racing. But for the most part (say, 75%), it's junk horses and mediocre horses that are filling up kill pens in Mexico.
Backyard breeders need to stop breeding. Period. Big production operations need to cut back their foal crop drastically.
And there's no excuse to not geld colts. If they aren't high quality animals being used for breeding, they need to be cut, because eventually, they'll jump the neighbor's fence and breed his mini mare. Or hurt themselves trying. Not to mention, stallions are dangerous and unhappy horses. Nature tells them that they need to reproduce--they've got that constant internal drive. But if they act even remotely like a boy, they get in trouble. How is that fair? They're constantly nervous and on edge....because that's how they're programmed. They have trouble keeping weight on. Geld them, and they calm down. They're healthier, happier, and saner.