Which is to say Sussman could effectively, for the purposes of this course, get _any_ license for free-as-in-beer.

So the actual decision would purely be on some other grounds. Since Sussman is a world renowned CS teacher, I choose to believe he made his choice based solely on whether it was most suitable to teaching CS.

(This is not an unreasonable belief: The concept of "Free Software" guarantees that the student is able to take the software apart to see what makes it tick. That is obviously a very valuable property when learning how things work!)