As a certified athletic administrator let me tell you that this is an area that many states are going into that they are not and should not go. They are playing on the ignorance of the general public. No one and I mean no one is allowed to dictate what you are allowed to do on your own time. This is clearly outlined and has been backed by the courts. The coach, who is an employee of the school system, IS governed by the high school association, but the players are only governed while they under the jurisdiction of the school, which means during practice and game times. What you do on your own time is not for them to govern. This has to be legally challenged to be overturned.
The only problem is that it would take a law suit or threatened suit against the high school league to get this overturned. This is one of those situations where high school leagues have stepped over their boundaries and they know it, but they will let it ride until somebody challenges it in court. The ACLU and anyone with a decent lawyer would get this overturned.
Problem is that most people believe that schools can do what they want, and pretty much they can, and do not challenge rulings, even when they are wrong. They play and act on ignorance, and the truth is, that it has to be chalenged in court or through the courts and most people do not have the money to do so, don't want to rock the boat or just plain don't care, so it never gets challenged. But I can tell you that any lawyer worth his salt would have it overturned without any trouble and force this or any high school league to stay out of peoples business away from the playing field.
Ty