Having knowledge and experience in this area, I feel :
Posters expressing surprise that this is a thing (both the mixed sex wards and the assaults) are part of the problem.
It is a big issue, but people, in my experience, simply have no idea of the scary realities of psychiatric inpatient treatment (on multiple levels including restrictive practice) and don't care to be enlightened
People who experience significant enough MH issues to be hospitalised, also experience high amounts of social and familial abandonment and people instantaneously doubting the truth of anything they say.
My friend has been assaulted and taken advantage of multiple times by men on psych wards. She is young and vulnerable.