Its about privacy, the fact that male and female are, indeed different, and bathrooms reflect that. This blending of genders in the minds of the young is going too far, confusing kids and, apparently, adults. I, for one, am glad to be male and am certainly glad females are different. It they become more and more like me, I am not going to be nearly as attracted. Who knows where that will lead, and the dwindling demographics of Western cultures might just be a clue.
I say lets keep the genders separate and interesting.
I would agree that those who have no clue as to what they really are should have a common bathroom that they can voluntarily access. To have everybody else be forced to relinquish their own beliefs/privacy for the few seems a tyranny of the minority, which is something to be avoided at least as assiduously as a tyranny of the majority.
Totally disagree with your view that the nation will endure this constant escalation of pushing things like gender beyond the norm and deep into deviant. There are, and should constantly be, lines drawn in the sand as to how far things should be allowed. Anarchy is not what preserves society.