Whether someone is a victim of assault or rightfully practiced self-defense is often a difficult question dependent on the states of mind of the people involved in a volatile situation, remembered through the veil of faulty human memories. Details like who used force first are pretty much impossible to determine without a video recording. Of course, police officers are as fallible as anyone else. Defamation requires a willful disregard for truth, and I have a hard time believing that “they committed assault” would be defamation when “they got in a fight” is accurate.
For what it’s worth, I consider myself a liberal, and I went to a liberal arts college cut from the same cloth as Oberlin and wrote anonymous posts debating what I perceived as the excesses of liberal campus activists.