I honestly have no idea why the leggings were banned. I never wear them. I like jeans. Supposedly in the same move they got rid of yoga pants too, which people really liked wearing because we can't wear sweatpants to school and they were super comfy. They can be worn with a skirt or dress that reaches fingertip length when your hands are relaxed by your side.
To address the argument about being able to dress professionally, I call bullshit, especially given the circumstances of my school. Most will remember I'm in a law academy and on debate team, and frequently I will have to dress professionally for events and presentations. I have seen people in full on suits and ties looking more professional than some adults I know. One friend of mine even wears a lapel pin he got from a congressman. Yeah, we're those kinds of people. We know how to dress professionally, but when the time doesn't really need it, we like to wear clothes that are comfortable to learn in that aren't distracting to us about how uncomfortable we are in jeans or whatever. And while I love wearing slacks and all, coming to school looking like this 24/7 is insane.
None of the leggings I ever saw being worn were sheer. Tight, yes. But I wear jeans that are that tight and I never get called out on it. And when they made the announcement about the leggings being banned in a student code of conduct assembly, most of the boos came not from the girls but from the boys. It seems like people were calling it a distraction to boys, which makes the whole thing even more bullshitty. Calm your boners. What's more distracting here, someone being comfortable or a teacher taking away from instructional time to reprimand someone for not following dress code?
Also, that boy I mentioned in the OP made it to fourth period when an assistant principal followed him into the theatre and said "Really?"
The boy said "Yeah, really." But then went and changed.