If you really believe that, you scare me. In most cases the obvious answer is the right one. Obvious answer here based on what the guy did after his review was that his performance before the review was less than exemplary. There are certainly better ways to fight bad reviews than mucking up a million dollar system. To me that shows a character flaw which means he probably did other things to warrant the bad review.
Or he is just a scapegoat and quit over a bad review, did nothing to the system, but they screwed somethign up, cant run it and now they are trying to cover their asses by claiming it was sabotage by him.