with similar play as not a handball (but I'd like to see video to form my own opinion if that video was really close to instance here).
But if ref called it right, what a terrible rule! They are now trying to judge intent?
Even if defender was in the process of moving his arms to his side, defender still got the advantage of blocking the shot with an outstretched arm. The body blocked none of the shot. The outstretched arm blocked 100% of the shot.
That is extremely subjective - whether an arm position is natural or unnatural.
I agree that the defender didn't purposely try to block the shot with an outstretched arm; nevertheless he and his team got a huge advantage by blocking a shot in the box with an outstretched arm.
If the leaders want to encourage offense, then they shouldn't be making more rules to help defenders in the box. defense already has enough help in the sport.