At root - yes. Simple explanations will not suffice.
PC cannot just be explained as expedient careerism - because PC is something new.
Once a system of political correctness had been established, it became expedient for careerists to spout PC; but why did the system of PC become established in the first place?
And, having been established, why did PC not immediately get changed? - given that it is obviously irrational, obviously self-destructive?
The self-loathing craziness of PC is not a subtle thing: it is as obvious as having central London looted and burned for several nights in a row while thousands of police stand by watching and the media conceal the racial identity of the rioters.
Once it is up and running and stable, to be PC is merely expedience; but the creation and sustenance of the sociopolitical framework which defines what is expedient still needs to be explained.