I don't know if you caught that. But for me, "they pled guilty!" is meaningless. People are coerced into that all the time. So speaking generally, to those who think saying that is shorthand for winning an argument, it's quite silly.
In general it may not mean much. People do plead guilty even when they aren't, for many reasons, and even more so with minorities. In this specific case though we're talking Oberlin students, not some poor kids from the ghetto, already making this less likely, and even worse, while I would not necessarily expect rioting progressive students to make any sort of logical and factual argument, I would expect better from the administration. But interestingly, they also never presented anything based on logic, let alone facts, and never even made the claim that the assailants were coerced to plead guilty, witnesses bribed, investigations botched. They just took the narrative that fits with their ideological view and ran away with it, facts be damned.