I agree with the thrust of post 15 but for the sake of breaking part of this down:
because it is the defining nature of an ideology to no longer have free discourse amongst equals; an ideology says of itself: "We found the truth, and it is xyz."
Is that ("finding the truth and saying it is xyz") not exactly what Epicurus does when he says things like:
Pleasure is the absence of pain...
Believe that a god is a living being blessed and imperishable.....
So:
Are we supposed to "leave everything uncertain and go on explaining to infinity or use words devoid of meaning"? (letter to Herodotus)
Are we to "go on studying till old age the subjects that we ought to be ashamed not to have learnt in boyhood?" (Torquatus in On Ends 1)
Or are we to:
"give definite teaching and not profess doubt?" (Diogenes Laertius 121)
"never cease proclaiming the sayings of the true philosophy." (VS41)