Many advanced practitioners don’t even have a good grasp of college level/post-grad pedagogy which they’d use more in their day to day work.
Using a skill isn’t the same as teaching it, and just like anything else there are plenty of fallacies to be had. I’d be more persuaded by angry hot takes from High School teachers worried that their students aren’t going to hit the grades they deserve / learn the things they need than anything else.
Even then, single high school teachers experiences are closer to anecdotes than actual pedagogical research, with which the original proposal is backed.