I agree Griff11. The horse had clearly lost his action. If the man who was riding him couldn’t feel what everyone else could see, he shouldn’t be riding. Often you see “rider looked down as if something was amiss” in reports of horses pulled up. Townend never stopped riding to check the horse was OK. In all my 50+ years of watching racing, it was the most sickening thing I’ve ever seen.
I have noticed that several horses reported deceased have “found to be lame post race” after finishing their final races lately. Don’t recall this being an issue in the past. Perhaps racing authorities should be concentrating on educating jockeys to pull injured horses up rather than harping on about the whip or tinkering with fences.