Alceste, you keep focusing on the legal aspects, but there is more to social and political life than the law. 

This incident reflects a political climate in which students have incredible power to victimise respected academics for peccadilloes, and no one will defend them because they  cower in terror at being the next victims themselves if they do. 

Thank goodness in this case the academic was safely retired and his livelihood was not at stake, so he could just walk away.