While it is fun to point out the selfishness and hypocrisy of the PC elite, it would be an error to imagine that political correctness is explained by this: that PC is merely an indirect way in which the elite can pursue its own self interest, or that PC is merely a technology in a power struggle between sectors of the ruling class.
PC is indeed all of these, but there are an infinite number of such ideologies, and the interesting question is why PC has been adopted universally throughout the West and why it has spread through all the institutions of the West despite PC being very obviously self-destroying: despite PC being suicidal.
What is interesting is why and how a suicidal ideology can thrive and be so resilient in the face of... well, in the face of reality.
Or, more exactly, in the face of reality as spontaneously perceived by common sense.
What is interesting and novel about PC is its reality-denying aspects.
Or, more exactly - since all religions deny reality in the sense of positing a higher reality than the everyday - how PC is reality denying in the absence of any concept of a higher reality.
Political correctness denies common sense reality, but lacks any method of perceiving another reality higher than common sense, and denies any such possibility.
So that it is not merely rhetorical to term PC nihilist: nihilist is simply a term describing of a belief system which denies reality.
There are, of course, degrees of nihilism.
A lot of people believe that there is a reality, but have reservations concerning how much individuals may know of reality.
But PC is a very extreme form of nihilism, in the sense that it denies knowledge of reality and also denies any possibility of knowing about reality.
Of course, at an operational and everyday level, PC pretends to care about and know about reality - but that is not what it does: implicitly PC believes that reality is socially-constructed; and that there are no constraints to the social construction.
Very radical, too, is the implicit belief of PC that reason is not valid; that reason is, indeed, socially constructed, hence contingent, hence without objective validity.
But I do not see nihilism as being linked to an active wish to destroy (maybe it is, but I cannot perceive this link) - and the deep nihilistic 'beliefs' of PC clearly do not prevent its having motivations.
The root of the problem is that as progressive, radical, atheistic, this-worldly, leftism evolved - it did so by challenging basic beliefs and convictions with which humans are born.
In all human societies until recently in the West, humans came-into the world with built-in assumptions - and human society used these inborn beliefs (or, most of them) to develop ideologies.
So, all ancient ideologies incorporated a kind of trust: trust in the reality of the world (various combinations of the visible and the higher world), validity of reason, reality of the soul etc.
But the radical tendency developed a method of wholesale but piecemeal doubt of these assumptions, one at a time.
(The ancient cynics and skeptics had tried out radical systematic doubt, but this was immediately and obviously self-refuting; whereas piecemeal doubt could masquerade as common sense.)
Some assumptions were accepted (for the moment) and were used to challenge other assumptions; in a kind of rotational process - until doubt had been cast upon each and every assumption with which humans were born.
So the culture of atheistic, leftism - which is now PC - stripped away the basic toolkit of assumptions with which humans were born into the world. So the culture of radicalism rapidly made humans helpless in the face of reality; took pre-designed people - created for this world - and made them into (psychologically) formless blobs.
The hope behind this was that formless blobs would be amenable to re-programming - and indeed they are (many of them). But, in an unreal world, what to reprogram them with?
The formless blob humans created by PC deprogramming are being filled with the highest thing known to PC; which is impersonal abstract altruism; they are being filled with the idea that the highest goal a human can aim-at is to impose upon human behaviours an abstractly virtuous system which does not depend on individual humans, does not require moral humans, does not need human choice - human agency.
At a deep level, PC has become a program to destroy humanity (destroy not the physical form of humans, but destroy their agency, freedom, choice etc) - and this is not seen as a bad thing to do, since humans are intrinsically selfish animals, and therefore the highest imaginable thing in the PC world is an abstract system which shares-out 'goods' despite what humans might feel about it.
Of course PC cannot justify that imposing a system of altruism is objectively a valid endeavor. Because no endeavors are valid. There is no valid positive goal for PC - it is negative and reactive against our spontaneous perception of selfishness/ injustice/ corruptibility.
PC is therefore always working-towards - and if it ever actually arrives and achieves its goal, then it will collapse from its internal contradictions.
That collapse might still leave humans enslaved to abstract systems of altruism, but the humans so enslaved would no longer be politically correct.
(Something of this sort seems to have happened in the USSR by 1989.)
My point here is that PC has evolved logically from a set of skeptical moves, from an attitude of radical doubt, which actually originated in the West around the time of Abelard in the medieval Catholic universities.
Is it really plausible that something so abstract, so philosophical/ ideological, so hifalutin, so far removed from the everyday and the practical could be the cause of Western suicide?
Well, yes. Only something of that sort could have the capability of getting humans to behave so anti-biologically as does PC.