This information is taken from my daughters college Philosophy text book, "The story of Philosophy" by Bryan Magee;
(This Group) tended to regard their beliefs not just as personal opinions but as scientific knowledge, and therefore as "known" with absolute certainty. This gave them enormous confidence and made them famously intolerant of all alternative views and opinions; and whenever they got into power they forbade the publication or teaching of any ideas that were incompatible with theirs. Since (this group) claimed to predict the furture developments of society with scientific accuracy, (their order) was believed to be "inevitable", and this meant that, (this group) were, so to speak, on the side of the future. What they believed in and wanted was going to happen regardless of what everybody else did or said. The whole world was going their way. As they liked to put it, "history is on our side," and their opponents were going to be consigned to the dustbin of history. They were living, not just in the present but in the future too, and before anyone else got there.
Guess who that group was......Marxism
I guess the governing body took the communist playbook and ran with it! Mav