Now, just about EVERYONE that is staff has been sexually groped by this woman, several times over, and there is basically nothing we can do about it because the woman is not in her right mind.
Are you sure? In their right mind or not, laws against sexual assault are not just there to hold the one doing it accountable, but also to protect people from falling victim to it.
So it seems that you can relativate it and laugh it off, no big deal.
But what about people who don't fancy being touched, either because of principle or earlier trauma? Are they disqualified to work in psychiatry? Would you get fired if you demand measures are taken to stop the woman from sexually assaulting people (straightjacket?) That would be rather discriminatory, and either in complete disregard to every person's right to the integrity of their own body, or very blunt in the case of 'sorry lass, because your daddy / teacher / priest / mom touched you in bad places when you were 9, and you can't stand being touched sexually, you are disqualified from pursueing a career that involves working with psychiatric patients'. I think that the protection of the individual (that is involuntarily sexually assaulting people) does not outweigh the protection of the group (people who don't like being groped).
If a patient is repeatedly violent and breaks staff bones, even after repeated attempt at non-physically restrictive correction (isolation ward/chill-out room/talks with the shrink), it's straightjacket and anti-spitting mask (or just a huge dose of government approved harddrugs). Just because being grabbed by the balls or in the pussy doesn't put you in hospital doesn't mean that it won't be even more traumatizing than breaking a bone to quite a few people.
Are you sure that the 'nothing we can do about it' comes from a culture in some branches of healthcare where nurses and other non-senior staff don't dare to stand up for their rights because they are replacable?
(I think your management needs to be careful, damage claims in the US are insane, all it takes for bankrupcy is one groped employee to claim sexual trauma and sue for millions for not providing a safe work environment.)