I was in the band at Nebraska, and everything, everything, revolves around sex and alcohol. The band director is not in charge of parties or socializing, and unless he promoted this behavior or looked the other way when serious incidents were brought forward, the director is not responsible.
I would say that the director is responsible for encouraging an atmosphere of maturity, responsibility, and positive camaraderie however possible with college age kids, but the stuff in this report mostly goes on everywhere. That doesn't mean harassment should be tolerated, but the director can only do so much.
The worst thing was probably the negative PR when this info came out, and the school had to make a quick decision. Ohio State's band is well known and well respected. Our old band director at NU used to say you could work for years to build a positive reputation, but only one misstep could ruin it all. Of course, that same director got arrested and convicted for soliciting sex with children.