The disturbing thing is that, maybe, he hasn't changed at all since then... he seems to have all the insecurities and fantasies and passions he had as a child, and uses his adult resources to realise them.
He seems to honestly believe that he is doing nothing wrong, and that the adult mindset that pollutes his playing is the 'evil'; his fundamental flaw is of course that he doesn't realise that if he's going to use resources of the adult world he must accept that he's entered it and must abide by its laws and values.
OK, this thread is getting way off topic, connections to the Muppets are oh-so-tenuous... but maybe he could be one of the latex creatures in The Dark Crystal