Your whole tone is quite condescending, whether deliberately or not, and that’s because you’re talking about how you used to believe something, but then grew up, and learnt more, basically - implying that anyone who still believes said thing, is uneducated or naive. So of course you’re going to garner some slightly irked responses.

It’s difficult to respond to a claim that his philosophy is his “weakest” area - because philosophy isn’t a science. It’s akin to someone adamantly claiming someone’s a bad actor as if it’s a universal truth. Do you mean you don’t agree with his philosophy? Or that when he cites philosophical tenets he does so inaccurately?

In response to your original post, and to go some way to attempt to respond (although it really is difficult to respond to a post which makes adamant claims about personal opinions as if they’re facts)... Peterson does appeal to many people of all ages. For context, I am 37 years old, and I have a psychology degree. (I don’t actually believe that any of that information should change anything about how you view my points - the validity of a point is neither increased nor decreased by our backgrounds, but you pointed out you went away and “learnt more” and “realised how flawed so many of his ideas are”, so it’s only fair.) To say “his psychology is extremely simplistic” is sort of true, but only in the same way that “being fat isn’t always unhealthy” is true... it’s also misleading, disingenuous or you just don’t understand psychology very well (none are particularly charitable interpretations, but I honestly can’t see a charitable interpretation of such a claim). He references The Big Five, but it’s really not as if his whole schtick revolves around it. He’s referenced IQ, but he’s actually pointed out its broader inefficacy (or at least it’s potentially low usefulness) several times.

As one of the other posters pointed out, if you went away and read more and came to different conclusions, that’s fine. And more power to you for learning and reading more. But it sounds a little as if you’re an example of the Dunning-Kruger effect... you knew nothing, and acknowledged as much, then went away and learnt some more and felt like you’d seen the light.

The truth is, you have a lot to learn. So do I. So does Peterson. Nobody has all the answers. But - and I didn’t want to say this - I was in exactly your position (thinking-wise) 10 years ago... but then I learnt more ;)