By the way, McCoy's behavior in Tholian Web was about on the same level. And for that matter, in Paradise Syndrome too. Unprofessional, non-supportive, inexcusable in a senior officer.
I chalk this up to the whole "missing the mark" aspect of the third season. Someone glanced at a few episodes in the first two years and saw "McCoy is cranky and fights with Spock" without paying attention to the layers below. Bones was still insubordinate in the previous seasons, but for the most part, it was their "banter." In the later episodes, the banter slipped and it became kind of nasty.
But I like the idea that McCoy gets bad reports and is saved by being Kirk's pal. It would explain why Bones never seems to have an assignment under anyone else in the films. He simply quit the service, to be called back by Kirk in TMP. Nobody else wanted to deal with his bullshit.