What is the benefit to OP in doing that, PP, now that he has taken another job? I can see plenty of risks if OP does that, but no benefit in poking the hornets nest.
There is no benefit to the OP but there is plenty of benefit for others who may come afterwards.
People use forums and websites to report on bad hotels or rubbish restaurants - there's no benefit to them at that point, but people who are interested in staying there or eating there will benefit from reading about their experiences - same with this situation.
All the OP would have to do is say thanks to them for taking the time to interview him/her again but as they didn't get back to them, they've taken another position. No finger pointing, but if there is something going on backstage, then the boss should be able to read between the lines from that and work it out.