I hear you Dave, but I still think that their antiquity is nothing to do with it, or their suspicion of outsiders. The poor buggers in the interior are kept down and the general populace is oppressed apart from the relatively new and highly prosperous professional classes, plus the long standing elite. No wonder the establishment doesn't like outsiders, brutally punishes free thinker and dissenters, censors the internet etc.
They should be suspicious, as the game's up if not. Self preservation for the elite, that is all.