Honestly that's just how school is. If you want an airsoft club, you'll just have to make one on your own time and not on the school's. That's how we always did it. We figured if we wanted rules our way, then we wouldn't run things via 'school club.' Instead we just had our airsoft clubs set up on our own time and that way we couldn't get in trouble for them because of any random regulation. (And nobody could get sued by the crazy helicopter parents for chipping a tooth.)
Bear in mind, schools and guns, or gun related anything, video games, movies etc. Just don't mix. And with school shootings and whatnot, I don't care if they want to take precautions. I've been in some nasty situations with students on campus with weapons. Hell one of the guys I went to school and used to run with became a murderer and is serving life. Point is, schools are paranoid about violence and I'm not going to say I blame them. Yeah there are very stringent rules, and hell some don't even make sense. But you're only in high school for 4 years out of your life, and it's not meant to be fun so, alas you'll just have to deal with it.