Free speech does not entitle anyone to indoctrinate their opinions on those that wish to learn truth. Free speech has nothing to do with this guy teaching. Everyone has an opinion. There is a great difference between "opinion" and "fact" most of the time on the Left.
Hell, my "opinion" is to make an oil slick out of much of the Middle East, but I wouldn't "teach" it to anyone!
Well, here's an interesting thought from the professor:
" So I try to bring in politics in a way that I don't try and hide it. I don't try to pretend to be neutral. What I try to do is highlight the assumptions of my politics. So for instance, in this critical thinking class, [I say] 'Here's the assumptions on which I make my judgments. Now let's examine the assumptions. You might disagree with them. Why? What evidence would you bring into this?' It's kind of a modeling of engaged political discourse, which I think needs to happen. But you know, professors often get very afraid that they'll be criticized for being political. To my mind, that's what we're there for, is to engage."
But you're talking as if teachers don't always give their opinions. Of course they do.