As someone who grew up with Voltaire's maxim "I may disagree with what you say but I will defend to the death your right to say it," I am troubled by the implications of the article. 

However, from experience, it rings true. I think that the professor is suggesting that some people — perhaps most people — are literally beyond reason. If that's true, then it does bring into question the efficacy of the notion that society necessarily benefits from the "market place of ideas." 

In Canada, we have limits on speech. You can't yell "fire" in a movie theatre just for fun and neither can you use speech calculated to incite animus or hatred against indentifiable groups of people. 

We now live in an age where speech can be quickly and easily weaponized by people and against people. It may be that it's time for guard rails — or perhaps that's training wheels — to shield society from bad faith dealing, mendacious, ignoramuses like Hannity.