So what? Report him to the police, do an investigation, fire him if he really did what he's accused of, let the court deal with the rest... I don't know why removing him from the internet helps.
- The organization signaling to stakeholders that they condemn and take appropriate action against behaviour.
- The organzation engaging in damage control, minimizing future exposure of events linking back to the organization.
- Penalizing transgressive behaviour in a professional setting, through sanctions and revocations of merit, reputation, licensing or employment etc.
Actually, breach of contract could lead to lecture material not being legally available, if a lecturer has sole ownership of such. It could also be that future use of say, recorded lectures, involves compensation to the author. If an organization want to cut ties to the author, or just withhold compensation for a time, they might refrain from using the authors material.
It's a shame, but any other solution feels like it's a broken stair just waiting for someone to trip over it.