The penalty was for someone shoving someone else in an area of play that did not interfer with the ball and the attack. Therefore I would have either had a chat to the defender or carded him, but I would not have given a penalty. Perhaps a free kick. I hope this does not come in to football. All I want is goal line technology and if the ball did or did not completely cross the line.
In terms of the Laws Of The Game, it's irrelevant whether there was interference with the ball or the attack. The shove itself is the offence.