And what about his right foot? Is that further away from the target - I think not.
No one steps backwards in order to make a throw - period. The action of drawing the throwing arm back promotes, like in a golf swing, a pivoting motion whereby the weight shifts onto the leg furthest away from the target.
Who said anything about STEPPING backwards? We're talking about a PIVOT here. It's rotation and weight shift.
And we're not talking about throwing something with a running start either; that kind of motion and a golf swing have zero equivalency. We're talking about something more like a pitching motion.
In which case, yea, your right foot is farther back.