I don’t think a show horse whose legs were clipped close is one who “just doesn’t like being sprayed”… to the point that the professional grooms have to hold a front leg up to get the job done. Nosirreebob, I think that horse was reacting out of pain.
I would bet on the hind leg treatment being done in order to make the horse “more careful” behind. Whether that means not touching a rail, or merely being tighter with his hind end, I think either applies and could apply to some hunter pro looking to optimize the horse’s form over fences.