There are many lecturers, profs out there talking expressively about various topics that they’re actually qualified in.

I think a better explanation might be that he’s always had core beliefs that lead him towards these conclusions, but didn’t have the freedom to express them when he didn’t have the clout to balance the backlash. Recall his fame started with his profound opposition to respecting alternative pronouns. I’ve heard him say disproven stuff that dovetails with his worldview in his psychology class with utmost confidence, prior to him getting on anyone’s radar. If he went the deep end as a result of the criticism, that wouldn’t explain his earlier problematic positions.