I too tend to think that what is really going on here is wounded pride - they put so much store in those goddamn useless bullet trains that the immediate response is to pretty up the wreckage so as not to be reminded of it. Secondarily they figure if they remove or destroy the wreckage people will start forgetting and won't be able to ask questions. They were really hoping to export the technology (which they got, after all, for free from Japan and Europe) but I think that is dead for some time to come - who's gonna buy a train from people who can't even operate them safely?
For them to be crushing the wreckage and cleaning up the site, when they haven't even published a list of the dead and missing, is truly revolting.