Recent IFAB interpretations of the hand ball law take into account using your arms to make yourself bigger. In that respect I agree with your points; his arm was away from his body, making it more likely that he block any shot. However, the player was only a few yards away from the shot and had no time to react. I believe the referee saw the outstretched elbow, and accoding to new interpretations, gave it, not knowing that it hit his back shoulder first. Referees with a hard-on for the rules give that, I would not. Referees have to be 100% that there's an infringement and not just guess at it, especially in such an important situation.