This is one of the things I find most frustrating, and increasingly frustrating: not so much that it happens, but that so many people cannot see that it is happening.
An example is research into intelligence, specifically into the combination of the inheritance of intelligence and group intelligence differences.
The FACT is that people presenting arguments or evidence to show differences in heritable intelligence between groups, have been severely punished by Leftists since the mid-1960s.
To put in mildly, this state of affairs severely distorts both research and public discourse, with incredibly far-reaching maladaptive consequences for social policies; yet, people do not take account of this distortion, or assume that they can readily correct for it.
The same applies to arguments about sexual orientation, immigration, poverty, the redefinition of marriage... the list is a long one.
Leftism has not won these arguments, the Left has simply punished those who argue on the other side: and when I say 'The Left' I mean particularly Leftist intellectuals in the mass media, public administration, the education system, and bureaucracies generally.
While at the same time denying that they are doing this! And being believed!!
The consequence is on one side to sustain a truly deplorable state of dishonesty, and on the other side a near total lack of awareness of this state of dishonesty.
There have been plenty of examples of coercive repression of opposition, indeed something of the sort is necessary to stable government - yet has there ever before been a situation where so many people are unaware of the coercion, deny the coercion, or think that it doesn't make any significant difference, or that they personally can easily 'see through' the dense cloud of swirling lies which surrounds them?
What can be concluded?
Our society is far more corrupt than people realize - why wouldn't it be? What's to stop it? But just how corrupt it is impossible to know, even approximately, since any 'evidence' consists of lies built upon lies.
Our society is far less smart than people realize, because good arguments are punished and demonized so bad arguments (or no arguments at all, but merely faked moral outrage/ scapegoat hatred) wins vital arguments by default.
In sum, we live in a world ruled by dumb liars, who get dumber and more dishonest every day - who think they are smart reality-perceivers because they are talking so loud and fast, and because nobody argues against them except disgusting losers - and this continues because the dumb liars rule a world inhabited by short-termist secular hedonists who do not have any reason to care whether or not the above description is true; since they regard truth as whatever is expedient en route to happiness, and reality as something socially constructed and open-endedly re-definable.