It is hard to take the "post-truth" critique movement seriously, given it seems to suffer from the very defects it claims to deplore: dishonesty and a disregard for facts.
Ostensibly the movement bewails that politicians are bending the truth and that the public is willing to swallow lies — phenomena as old as the hills. However, what is likely to be a greater reason for cognoscenti discomfort is the tendency, allegedly increasing, to question the wisdom of supposed experts. The discomfort may be largely about loss of power, but is wrapped up in concern for veracity.
The movement likes to claim that many people's attitude to facts is selective at best, but it's not clear that it scores any better on this issue. For example, the movement likes to cite Brexit as an illustration of the post-truth tendency: Brits who voted to leave the EU were allegedly motivated by considerations that are not supported by facts, and allegedly ignored counterarguments based on hard data. None of the articles about post-truth I have read takes note of the fact that UK voters' scepticism about official pronouncements may have been justified, if those pronouncements were deliberately slanted towards what officials believed was the 'right' answer (i.e. Remain).
If the alleged loss of faith in experts has been triggered by increasing awareness that their advice is driven partly, or even predominantly, by factors other than truth — e.g. what they consider to be the greater good — experts may need to look for the source of the problem in themselves.