There is an additional psychological mechanism at play here to be aware of, which is that some criminal actions taken by the government (in order to protect ruling class interests) would destroy the legitimacy of their claim to power if admitted to. The importance of controlling the narrative around so-called State Crimes Against Democracy therefore becomes existential.

Marxists are more aware of this dynamic because they understand the nature of power structures. It's also to be the same reason their theories are viciously attacked by the ruling class.

Edit: Did I say something rude?