As for why he should be trusted? He has achieved heroic status for putting his job on the line to stand up against political correctness overreach. He has riveted tons of young men with his demonstration of the archetypal parallels between various pieces of Western mythology, Christianity, mainstream fiction, and psychology.
Sometimes he has me nodding my head, other times I'm shaking it in disbelief. I know very little about Jung or Nietzsche. Sometimes I worry I may be suffering from the Gell-Mann amnesia effect. [0]
[0] https://www.goodreads.com/quotes/65213-briefly-stated-the-ge...
I've seen his polemic rants on Youtube and they appear to be so mean-spirited and ignorant. He can't talk seriously about Marxism without bringing up Solzhenitsyn and confusing Communism with specifically Marxism-Leninism.
It would be better I think if he sticked to something I have heard he is good at doing - helping people out, rather than diverting into a strange strawman of someone extremely ignorant about political philosophy, though I suspect he must continue to do that in order to keep the little bit of fame he has managed to cling to since he was recorded "schooling" some (also ignorant) university students.
People aren't interested in his psychology, because the same people interested in him who weren't before are the people who'd be listening to Ben Shapiro and the philosophically ignorant, scientism-adhering side of Christoper Hitchens (poor Peter is too "normie" for them). He's not the first to so desparately cling to and place empiricism on a pedestal.
Out of interest, what expertise? He seems to be a psychologist who has multiple times talked about Marxism and postmodernism with the utmost ignorance of current research and philosophy. He also makes "authoritative claims" completely outside his "focus of expertise"[0] and is very wrong about them. Why should he be trusted outside his actual field of expertise?
[0] https://twitter.com/jordanbpeterson/status/40520012623631155...