An attack on free speech dressed up as an appeal to reason. Hardly a first but scary that it is coming from a professor at a top Canadian university. Where to start:

"Why don't we acknowledge that political belief is also an aspect of human behaviour in need of external control?"

Blind to the irony that tyrants the world (and history) over from Stalin to Mao to Hitler to present day Putin and Jinping agreed and agree entirely.

"Mere existence is sufficient for each of us to form a limited company in the world of thought. That's frightening!"

That individuals can think for themselves scares the author. That a person who holds that view is a professor is what scares me. 

".. denying access to the drug or even inflicting benign behavioural modification is far more effective."

The subject is participatory free speech and the author's conclusion is that it should be limited and restricted beyond current laws against hate speech. I must say he has rendered me speechless.