Sexual assault toward females probably mirrors the civilian population. It’s bad and getting worse. The largest share of sexual assault in the military is homosexual predators, though you’d never know it from all the mandatory training. Sexual relationships are not illegal, unless one or more is married or the conduct constitutes fraternization or conduct unbecoming.
As far as accountability, it varies (by rank usually). This case is rare, with most Command level officers quietly retiring, while junior officers and NCOs will get demoted, do hard time, and or get a BCD.
A Big Chicken Dinner is bad enough, but at least it’s not a Duck Dinner.