I just don't see how the answer to the #metoo problem is for girls and women to withdraw into a single sex environment. Look at the other spheres in which women are harassed - do we tell women who are catcalled on the street that they should walk down special women only streets instead, or actors who are coerced into sex by bullying directors that they should make women only movies? There would be an outcry. Surely the answer to sexism in schools has to be to refuse to tolerate it, not run away from it?
Also, I actually find the discourse around sexuality pretty old fashioned. There seems to be an idea that boys are all potential rapists with one thing on their minds, while girls are all potential victims who need to be tucked away chastely to preserve their innocence. I don't know about you, but I seem to rember having one thing on my mind too when I was 15! Girls need to learn to be powerful agents who control their own sex lives, choosing how much sex they want to have when and with whom, rather than pretending that it's boys who are interested in sex not girls, and that girls need to be removed to shield them in a sexless environment. That surely just perpetuates the idea that men are the desirers of sex and women are the gatekeepers - it's almost a throwback to the idea that boys who have a few sexual partners are studs while girls who do the same are sluts.
On a separate note, if the current trends around gender fluidity continue rather than being a blip, then I don't think SS schools will be sustainable as a concept anyway. Schools (and local authorities) are already struggling with how to approach issues around admissions policies, uniforms, toilets, subject choices, segregated boarding houses etc. If this continues, then I suspect the only feasible answer wil be to make schools as gender neutral as possible,.