There's a bit more to it than that though - specifically it has to do with allowing people who are transgender (not just any random person) being able to choose which area they are more comfortable in based on their own gender identity. It's a huge step forward in tolerance and understanding for the transgender community. I think all states should have these laws.
I'm sure that others will probably worry for the potential for some to abuse it, but honestly - if someone isn't transgender, they'd probably have a really hard time explaining why they were in the opposite gender's restroom/locker area. I mean yeah, they could do it, but then people would assume that they were transgender, so it doesn't really necessarily work in their favor to try it. Plus if someone is attempting to use the law for malicious purposes (or to exploit), then they'd be prosecuted for that anyways.
I think they experiment in Calli to see just how far they can push people with stupidity. This one is certainly case in point. Gonna do a question on homeschooling myself. Taught my own daughter to read. What a high!