I'm sure you didn't intend anything negative about Tennessee, Benji. I mean, surely you are not prejudiced against, or guilty of stereotyping, the citizens of various states. Reading the full story linked clearly shows that the practices in a few school districts do not meet the policies which have been adopted, policies which are supportive of gays. Tennessee has 95 counties and some of the cities have their own school districts, resulting in 135 school districts in the state.
Just because the Tennessee ACLU sent a press release to the media about several districts in the state doesn't mean Tennessee is the only state with a practice which might be considered discriminatory despite policies which prohibit such discrimination. It may mean only that the Tennessee ACLU is actively pursuing this issue at this time.
You may wish to read this summary of recent ACLU press releases on similar cases. One of the these cases involved San Francisco. San Francisco? No big surprise there, right?