You know, this speaks to so much of horse nature, and mankind’s whole history with the horse…their whole evolution, and ours. We’re the predator, they’re the prey. And they really do understand that they’re stronger than us. They’re not stupid. They’re just not wired like another predator. You could not whip a cat or dog like that, if they were that giant size (or even if they weren’t.) The horse is resisting, he’s just not directing toward his tormentor. There is a famous story about Friedrich Nietzsche, that the point when he snapped (mentally) and had to be taken off to an asylum was when he witnessed a cart horse being beaten to death in the street. I think the actual truth is, it didn’t all happen right then, but over a period of days he became more and more obsessed with the idea that the horse, by refusing to defend itself with its superior strength, had the moral high ground over all humanity (in that move the horse prefigured Gandhi’s own non-violent revolution!), which humanity (perforce including Nietzsche’s own) then became repugnant to him, and presto, nervous breakdown. My point is, if this incident bugs the sh!t out of you, you’re in really good company.