Junk mares? how has this not been rocognized?

Ok so I'm volunteering at Lucky Horse Equine Rescue where they try their hardest to rescue the foals from "junk mares". What they do is breed expensive mares, usually thoroughbred mares and then take the expensive babies away from their mothers very early so the mothers are sent back to be bred again. Meanwhile, a "junk mare" is bred so that she has milk in her utter for her baby, but instead her baby is taken from her and she is paired with the expensive baby so it will have a mother to nurse from. Now, these babies of the junk mares are usually shot right as they are born so the mother does not bond to the baby. But this rescue tries their hardest to step in and rescue the foals. How is this still going on? Technically it's not horse abuse and it happens right here in America. Although, shooting the baby is illegal here they ship the babies out to canada to be slaughtered where it's not illegal. How is this ok? There are no laws preventing it and the "junk mares" live terrible lives. I volunteer by helping with the training of the "junk foals" and ride the other abused horses they rescue also.