I don’t know why anyone saw a picture of a guy on a horse who was grabbing a guy on foot and decided that someone was being whipped. Makes no sense.
That mystified me too. He has his right hand reaching out to collar the guy, so the reins clearly have to be in his left hand, which is high and hidden by the horse’s neck and head.
He simply doesn’t have enough hands to be “whipping” anybody. But the left, ever ignorant, see what they want to see.