Mark, your opinion is heartfelt, but wrong.
A putt cannot be conceded after the fact. The referee was absolutely correct and the match was properly awarded to Shepard. Moon moved the ball before Shepard had a chance to concede.
Now, in match play, an opponent has the option of ignoring a rule violation. So Shepard could have ignored the fact Moon moved her ball. However, if Moon had become aware that she violated the rule before teeing off on the next hole, either through someone telling her or by her own recognition, she would be required to call the penalty on herself.
Additionally, this match had a referee assigned to it. A referee assigned to a match is required to assess any penalties witnessed. So even if Shepard had chosen to ignore the violation, it’s highly likely the referee would have recognized the rule violation and called the penalty — as she is required to do.
The fault all lies at the feet of Moon. Not Shepard, and not the USGA and R&A. Moon was the one who moved her ball without a concession.
I realize you want Moon to get a participation trophy and lose in a less heart-wrenching manner. But that’s not sport. When a receiver steps out of bounds by just his toe, nobody says “can you believe the DB or replay official pointed that out? Dude was trying to make a catch. He didn’t have any intent of going out-of-bounds. Award the touchdown so the other team won’t lose in such a sucky way.”
It does indeed suck to lose on a rule violation. But you only do it once.
As for courtesy and sportsmanship, that should have indeed ruled the day. The minute Moon realized she moved the ball without it being conceded, she should have said, “You’re absolutely right. I committed a penalty. I concede the match.” While technically unnecessary, THAT would have been the proper gesture of courtesy and sportsmanship. But instead you blame the player who did absolutely nothing wrong.