It's because people give the benefit of the doubt and don't want to think you're the kind of guy who blames the weak and powerless when bullies abuse them.
Is your attitude that it's acceptable for these people, who do not push the problem onto someone else, to be sexually assaulted? If it's not acceptable, why is it incorrect for the victim to seek help? If I were burgled, I would seek help. If I were mugged, I would seek help. Why is it incorrect for me to seek help if I am sexually assaulted by a manager?
Furthermore, given that my employer has a duty to ensure a safe workplace, why should I not upbraid my employer for failing in that duty, or advise them of the problem so that they can correct it? If I saw a dangerously loose carpet, I would tell them. If I noticed some buzzing wiring, I would tell them. Why should I not tell them that one of their employees is sexually harassing people?
In a normally common-sense forum here, I'm kind of amazed by the number of comments here that go straight to the nuclear extension of the other's point. Can we assume that we're all against sexual assault here and have a bit more charitable discourse?