Either that guy is off duty or hes recently left the military. He knows the guard clearly and its not his maye because his mates would already know not to go do that. There is no way a guard lets any civilian interfere with his horse like that.
Ummm, no one is remembering that touching the horses, even getting near the horses is absolutely prohibited. No guard on a hundred videos of people trying to get near the horse, pretty or not has let them. He is trained to yell very loudly at civilians that get too close to the horse. This was a set up.