In a sense, the core value of political correctness is fashion.
Fashion is not coercive, but everybody follows it (or, at least, everybody who 'matters').
So fashion is 'harmonious' - we all cooperate to make fashion, and we do so as a result of - well - propaganda I suppose. It is discourse (mostly the mass media) which informs and persuades people to follow fashion.
People follow fashion (merely) to belong; but to follow fashion is to belong; and the only (non-ceorcive) sanction is that if you do not follow fashion then you do not belong.
It all seems very mild; but it turns-out that this combination of reward and sanction is sufficient under modern conditions to ensure the domination and perpetuation of fashion everywhere and in everything.
So fashion is social harmonious, implemented non-coercively via discourse - and of course fashion provides novelty.
So, unlike traditional societies in which social harmony is static, often coercive and aspires to be eternal; and therefore has a tendency to be boring - fashion is dynamic and interesting because new and unfamiliar.
When we begin to get sick of fashion, and the novelty starts wearing off, fashion can either become more extreme in the same direction, or else a completely new fashion may be invented, or else a more-or-less-forgotten old fashion can be revived but with some twist, or several old fashions can be recombined.
Isn't fashion, therefore, an almost-exact analogy for the world to which PC aspires?
A world where everybody believes and wants the same thing - and so is harmonious and free from conflict and dangers; but also a world where the 'same thing' is continually changing (and progressing); and finally a world where all this is achieved (potentially) non-coercively by monopolistic control of discourse, of human communications.
Of course the world of fashion (and of PC) has nothing to do with real reality, but only to do with reality as perceived in human discourse - but this virtual world does go a surprisingly-long-way to seeming like real reality.
And of course discourse is only about humans, so it can only control human-caused harms and not 'natural' dangers - but it turns out that human perceptions of harms overlie and obscure reality to a surprisingly powerful extent.
So that discourse can frame and shape our perception of reality (because discourse fills the mind hourly, and what it fills the mind with is continually changing) - so reality seems plastic, and seems under human control.
So monopolistic control of discourse feels like it can almost control everything.
The only threats come when the would-be-monopolistic harmonious-yet-changing, mind-filling discourse is threatened with disharmony or when progress is threatened with statis or reversal.
This is why PC is so vicious towards dissent in discourse. Reality threats (starvation, disease, war etc) can be reframed with more layers of discourse.
Reality can 'do what it likes' without threatening PC, so long as discourse remains harmonious and changing - so long as 'fashion' is under control.
After all PC is about perceived reality, not underlying reality (which may or may not exist - PC is indifferent on this question of underlying reality).
But non-PC discourse is the real danger - because it threatens the seamless and harmonious integrity of perceived-reality itself.
Indeed, non-PC discourse - anything inharmonious with fashionable perceptions - is infinitely-threatening to virtual reality (after all, just one single loose thread might eventually unravel the whole carpet), non-PC discourse is the ultimate threat; and therefore political correctness is utterly ruthless in crushing and deleting non-PC discourse.