Living close the the Alabama border line has made me very wary of slaughter. When there was an equine slaughter plant in Alabama, horses were stolen all the time. They were processed so fast that nothing could be done. Sure slaughtering stolen horses was illegal. It was also profitable. The local plants give horse thiefs a good market for their goods. It will be profitable if there is a local slaughter plant.
Drugs are illegal. People sell drugs. If there were no market, there would be no drugs. Horses will be stolen if there is a market. The plant in Alabama routinely processed stolen horses.
Back in the old west days, they would have have public hangings for horse thiefs. It happened quickly and without appeal. Since public hanging is unlikely to take place, what do the pro-slaughter people propose to do about theft? I put years of my life, a lot of my soul, and a whole lot of money into my horses. I don't want them stolen and killed for profit.