For the life of me I cannot understand what you’re arguing.
Take slaughter out of the equation entirely. You and your little buddy 7 seem to be the only ones bringing that up ad infinitum anyway. Heck, while we’re at it, take out the number of horses on that trailer. I don’t think it could possibly be humane, but whatever. For the sake of argument, pretend it was.
This guy put 38 horses on a trailer with a man who had a prior bad history (including charges) when hauling livestock. NOT OKAY. He had a history of not maintaining his vehicles and equipment to the standard of the law. NOT OKAY. The driver apparently told him he did not feel up to doing the haul, and he told him to do it anyway or lose his job. NOT OKAY.
The haul was a minimum of 21 hours. We’ve already established that horses, by law, must be offloaded after 28 hours on a trailer. Guess what? By law, a truck driver can only haul for 11 hours before having to take 10 hours off duty (source). So. Either he was planning on doing this illegally and have the driver try to haul straight through (NOT OKAY, BTW) or…the horses would be on that trailer a heck of a lot longer than 28 hours. If hauled legally, they were looking at at least two, if not three days on the trailer. NOT OKAY.
Now, do we think that this man, who has prior documented history of not having proper health paperwork for his horses (to the point of having the State Veterinarian of Tennessee involved), who was under investigation by the State of Texas, and, given all of the above, was really planning on: A) unloading the horses (who, remember, are packed in there to prevent movement and load shifting); B) watering the horses; C) feeding the horses? If you think so, I have some oceanfront property to sell you. Not doing all of these things would be NOT OKAY.
So what in the h*!! are you defending?