"We shouldn't scrap our policy because of a small percentage of people who are transgender" just became "we shouldn't allow transgender bathroom rights because of an unbelievably miniscule percentage of people who cycle their gender back and forth on a daily basis."
Why are you assuming so much about this portion of the TG community? It was important enough to elicit a 40+ classification list for Facebook. Obviously the TG community considers allowing for choice and fluidity of that choice to be pretty important. And it just so happens the only truly TG person I know falls into that category.
I'm not actually assuming this. I'm basing it on a bunch of experience and research, and while the general determination these days - especially among transgender people - is that gender is a fluid, non-binary concept, the vast majority of transgender people in their daily lives live as either male or female an overwhelming majority of the time. It's the way we as a society have been set up, and it's why people undergo lifestyle changes when they become transgender.
And either way, the fact that we currently have people with
both female and male genitalia using restrooms and locker rooms seems to suggest we can come to some sort of understanding as to how to live with people who subscribe to
both (or neither) gender roles.