It's also always been possible to feign knowledge and wisdom with breathless enthusiasm or optimism. Fakery is fakery.
In general, we are not cynical enough. Humans have been out to take advantage of each other for as long as we have recorded history, and probably for much longer than that. Civilization is maintained in equilibrium between forces that seek to destroy each other, so you can and should assume that those forces exist and are currently and actively attempting to pursue their own gain at your expense. The heart of propaganda is convincing people to act against their own best interests. This is built into the essence of humanity.
What supports that conclusion?
Fear of being deceived?
It's a safeguard against trying to fight against things that "shouldn't be like this" and burning yourself out. It's endless in the real world too. The reason cynicism runs so deep is that it's warranted. After a period of time you turn around and ask yourself "if everywhere I go and everything I take a close enough look at makes me think 'this shouldn't be like this!' then what is it that I'm missing???". Eventually when the human operating system that underpins it all comes into view, the cynicism sets in. Sure, it's a lazy-ish answer, but in my experience it's a pretty darn good heuristic as far as heuristics go.
It’s to the point that discussions are derailed by it with folks who feign knowledge about a topic just offer cynicism. Anything that’s doesn’t work right the empty response is a conspiracy of “oh that’s by design” as if people would otherwise always have things working…
It’s endless online.