They need to get their history straight. Beyond a doubt, horses are more cared for and well-off today than when a million horses worked every day in the cities and towns in America, as well as fought in wars, built dams, bridges, the Panama Canal and whatever else for 16 hours a day or until they just fell over dead on the job.
Do they think we should take off their shoes and just release them into the wild? No, they probably don't realize that the hoof will grow over and around the shoe.