@“Cardinal Fang” I do tend to come on the side of leaving the materials out there - the lectures are what they are. Lewin is able to search Facebook even now, though one would hope if he decided to return to his dubious ways, the students he contacted him would block him within seconds.
If taking down the lectures is the only way to prevent people from creating relevant Facebook groups, I don’t know where I’d stand on the issue. I’m inclined to think that, when colleges start removing resources from the internet because discussion of them may pose some dangers to the participants, that allows Lewin and his breed to cause more harm still by hampering the spread of knowledge through their conduct.