I'd also like to add, just because your horse is head shy, doesn't like its back feet messed with, or is a butthead under saddle does NOT mean it was abused! Gah!
All that means is the horse has gaps in its training, or just doesn't like
certain things. That, even more than the word 'rescue' being throw about willy-nilly for purchased horses, drives me bonkers!
Now, onto the breeding issue part of the question.
The problem I see with crap
backyard breeders as opposed to just regular backyard breeders, is that crap
breeders will throw anything together as long as one has a penis and testicles, and the other has a working uterus.
I see no concern for the foal's potential, no research into genetic conditions of the mare and stallion, and no real idea whether or not a particular stallion will nick well with a particular mare. They just want a 'kyoot baybee', 'a piece of their mare', or think she 'deserves to be a mommy'. Blech. All bad, stupid reasons for breeding.
Backyard breeder isn't a dirty term. I've known several backyard breeders who produced lovely, talented foals. But then, their criteria weren't based on the cheapest stud fee, or whether or not the stallion was homozygous for the popular color du jour, or had tons of hair that they were after, and thought they could get it cheaper by breeding instead of buying.
I agree that the largest percentage of horses going to slaughter are products of the bigger, more prolific breeding farms. It's unavoidable, because with quantity, you're always going to get a glut of horses that are unsuitable, even if they were bred correctly. I don't like it, but it's an industry that generates a lot of money and a lot of horses for the general public, so it'll remain status quo.
However, responsibility for producing quality horses is on everyone's
head who wants to breed, NOT just the big farms.
If you're not breeding for a specific meshing of bloodlines, talent, potential, and ability, then you have no business breeding. That's
my beef with people, not the fact that they want to breed one foal for their own use.