Wow, you don't see that too often here.
But xzins is right. There were plenty of laws on the books that prohibited men from using the little girls rooms. The liberal enclave Charlotte NC passed a law that nullified all the state laws, so the State simply passed a law that prohibited the cities and counties from acting illegally and overturning state law by their own decrees.
What NC did was necessary in order to preserve the laws that have been on the books for hundreds of years.
People keep saying that, but public bathrooms didn't exist before the 30s. Everyone used to use chamber pots or outhouses that we generally not segregated by sex. Frankly I'd much prefer a return to single stall bathrooms instead of public ones.
I am all for any law that overturns or blocks a law passed to allow men to invade women's lockers or restrooms