Why some universities don't make their video lectures public ?

Speaking from a medical school standpoint, at least the one I work at, the lecturers are the 'owners' of their class content, including the 'performance' of the lecture. Without their permission, most of which want $$$ for each viewing, the school cannot put them up for viewing for free to the public.

Why do you think standford didn't make video lectures of this course "machine learning on graphs" public but decided to make the just the slides and assignments public?