>>he's probably got some disorder but when he's punching himself in the head publicly you can't help but wonder if maybe we should reevaluate our faith in his ideas

That's a bit of a leap of faith from a second hand account from a comment on a blog that related the event. I think it's safer to assume for now that the person who made the comment is not a native speaker (due to his name, and, obviously, being present at the talk) and is describing someone acting out the "stupid, stupid! stupid. How could I be so careless!" routine combined with hitting your own head, which I believe is a fairly common way to express exasperation, as "punching himself in the head".