Ahhh and herein would be precisely where you and I differ! You see his u-turn to be a welcome and honest criticism of a private school.

I see his u-turn as that of a disgruntled employee, fired from a place he previously enjoyed teaching who is now spitefully ranting about how dreadful it was (despite admitting he was desperate to stay working there!).

Sounds to me that he wasn't too good at his job and thought publicly singing his employers praises would save his job. And when it didn't he comes back to claim everything he said before was a lie and it really is a bad place (despite being desperate to stay there, you understand) and you should believe me now!

Which, of course, you will as it fits with your construct better than the other option!