Definitely right!
Had she walked away from the ball mark and come back later to replace it, such an omission might've not been an issue. But she's lifting the ball, moving her hand to the left and putting the ball straight back down again.
Maybe there was a spike mark beneath the original spot and she was trying to get away from it, maybe she made a simple mistake. What we do know is she didn't replace the ball in a situation where it would've been very easy to do so (or at least make a much better attempt). Maybe she does it out of a habit in case there is a spike mark beneath the ball?
As for arm chair refs calling in and it not being fair that people have a better chance of catching the top players who're shown on TV breaking the rules and everyone doesn't get an equal treatment. To me it's like saying the police shouldn't fine a driver for speeding because there might be someone else on the road speeding but not getting caught. Even a single violator caught is better than none, not only does it limit the actions of that person, it also sends out a message to everyone else. Not penalizing a player for such a breach would in fact penalize everyone else playing in the tournament and like has been said, the tournament committee's hands were tied once they were informed.
If you want to say "she didn't gain an advantage", I'd like to hear where you'd draw the line? The less subjective calls there are, the better we're off. Figuring out whether there was a serious breach in playing from a wrong place or not is enough of a task in the case of playing from a wrong place.
Also, I'd hate to be the guy sitting at home and noticing a rules breach and not being able to do anything about it. Especially if that person wrongly wins the event, especially a major.
Lastly, I'd probably change the rules so that you could repair spike marks beneath your ball when it's lying on the green. To save time I might not allow it elsewhere on the green though.