It's quite simple really.
It's handball if the hand is in an unnatural position at a 75 degree angle whilst perpendicular to the body and on the edge of the seven-yard box during an attacking phase of play (but not in the 3rd or 7th phases).
It's not handball if the hand is extended from the body at a contrasting angle to the hip bone and the offence doesn't happen within a 45-mile radius of Watford Gap or during the 4th, 9th or 12th phases of attacking play.
It's not that simple, because your arms are used for balance, if I pushed you, where do you think your arms would go, because of gravity, they would push out, stopping you from falling to the ground.
Watch players like Currie, Marsh, Greaves, Best, Waddle, Hoddle, see where there arms are positioned, using there arms for balance, when moving
Football players are moving at speed, changing direction all the time, adjusting their bodies, and you use your shoulders and arms for forward motion, and balance, you don't run with your arms down the side, it's a unnatural position, this penalty law is stupid, just say hand to ball, why are they trying to make football complicated.
Also watching the penalty against wolves v Luton, the player is off balance, with his arms outstretched and because the ball bounce up and hit his arm.