Accusations of sexual assault very often are "he said, she said" cases.  Seldom are there witnesses and, frequently, the defense is not "didn't happen", but "it was consensual."  Therefore, unless there is evidence of physical violence, any evidence of sexual activity is really irrelevant.  Given the circumstances presented in this story, it, likely,  would have been very difficult to gain a conviction on a criminal charge.

However, the University has its own conduct code and discipliary system which was applied in this case. The authority of a University to enforce such a system has been consistently supported by Courts.

IMO, The real issue of contention:  is there now a significant bias against men in the application of the conduct code?  The UO, like many universities, is struggling with the issue of sexual assault and how to lower the incidence of such behavior.  Is it possible that some "innocent" men are becoming collateral damage in this effort?..   IMO, it's a good question..