A juicy detail is that we don't even need to specify who they are. Always there are censors and those who try to counteract censorship, folks deaf and blind to history and people who listen to her lessons with a keen interest. Perhaps the special service existing out of time itself to adjust reality according to their needs is the natural limit of development of such a trend, see, e.g., The End of Eternity by Asimov, Great Work of Time by Crowley or Palimpsest by Stross.

Moreover, in some cases, le tiers état is thrown into the mix: for example, in some corners of actively developing countries like Indonesia or Bangladesh, whither the main share of the world clothing industry has been shunted, one may meet people who are still, nowadays, oblivious not only to the existence of Moon landing conspiracy theory, but to the very fact that the Man had once landed on the Moon… and thereafter forgot how to do it, possibly with a little help of the aforementioned reality adjusters. ;)