I'm actually surprised there are so many interpretations of 'pro side'. I wonder how many of you, like me, thought yours was the only one? lol. To me, as in any other sport, the 'pro side' is the side pros will prefer to play to (and miss on). It is the 'right way' to play the shot bc it gives you the highest win probability overall in the long run. Consider it pool analytics.
To the commit to the shot guys, you do commit. You commit 100% to hitting this side of the pocket. If you hit the shot as you intend, you make it. If you mishit slightly, you either make it to the other side of the pocket (perhaps cut induced throw puts you there?), or you miss the pocket on the other side and the OB ends up in a position more favorable to you than if you had missed on the other side of the pocket.
So, if there is a side of the pocket to shoot at that will provide you benefits, like making room for CIT, leaving a miss in a favorable spot as opposed to missing on the other side, or whatever other little advantage you can get that raises your overall win percentage in the long run....that's the pro side bc that is the side pros will play as pros are expected to play the highest percentage 'right shot'.