Why didn't the investigator subpoena the details about the accounts sending the accusations? That would have shown right away that the accusations were not "credible" and the university could have just dropped the investigation right away.

By the second go round, when the "y'all" message arrived, the credibility problem was obvious but the investigation didn't address it.

This sounds to me like a very limp bureaucratic response by someone just going through the motions, with no real effort to resolve matters.