I think they mean open plan single sex.
So males and females separate. Which is mainly private gyms ime or gyms with separate changing areas in public leisure facilities.
I don't mind changing villages with spectate cubicles or toilets the same.
But I absolutely want any changing rooms in shops etc single sex or proper locked doors rather than curtains and prisons etc to have male and female and then other 3rd spaces for those who think they identify as the opposite sex because they think gender exists and sex can be changed.
I think those who are victims of sexual and domestic abuse are more affected by this as it's more emotional for them as an experience.