> It is a property of the legal system.

A lack of something is not a property. The legal system lacks infinite number of things. Its not a meaningful definition if infinity is included.

> It's OK to treat men and women differently

And there we got a key disagreement. It is not OK to treat people different based on gender. Any such treatment will cause local power disparities, like bias that cause real harm.

>> why the law can't just provide this service for everyone
> my guess is that this is a "black lives matter" point

The reason why the law treat women as incapable to pick up the phone and contact the agency is rather obvious. Cultural views and values. The problem is the result of power disparities for victims, where gender has a seven time factor in dictating who gets support and who doesn't. As a group, victims of crimes is one that should also be discriminated against because of their gender.

> As recently as a few decades ago, women who put having children on hold to have careers were viewed as freaks.

One of the theories behind that "interesting phenomenon" that is gender segregation in nations like Sweden, it describe how women after world war 2 started to have more time to spend on a career rather than spending all time on raising children. Men however are still stuck with the same expectation to support the raising of children, so their role in the work market has been static. Neither is a cultural change away from women being solely valued for their ability to raise children, nor men being valued solely for their ability to support the raising of children.

> Nudists are not a social group just as chess players aren't

Unsure if you are aware, but I find that comment highly offensive. Lets just start by quoting the lead in the wikipedia article on Naturism. "Naturism, or nudism, is a cultural and political movement practising, advocating and defending personal and social nudity". There exist a long history of nudism philosophy, culture, and values. I find your comment similar to someone saying that black people are not a social group, just as people wearing glasses aren't.

People who believe that clothing is constraining their identity is equally discriminated by a law that require specific form of clothing on beaches. All the effect of discrimination, like being hurt and feeling rejected is current reality of those people. The stigma of "being the wrong kind of person" and having that discrimination not even acknowledged is very harmful.

> And where did you get 400 years?
>> One group has been enslaved for two centuries, and then forcibly put down for another two centuries

Two centuries, plus two more centuries, is four centuries.

And what material marks has been created for which black people exclusively can have? Is there a reason why the solution to those problems should not be used on society as a whole for anyone with the same material situation? It sound to me like you want solution to only go to people of black people because they deserve it more because of past injustice?

> I am not familiar with that experiment or its goals.

http://www.thelocal.de/20160329/is-germany-introducing-sex-s...

My question stand: Is it compatible with the successful abolishment of gender segregation in buses that the feminist movement fought for?