Everything is a technicality if you squint hard enough.

I see you’re confused about the concepts. You’re mixing “things that are legal (sometimes)” (smoking, but not on the plane) and “rights that you have all the time” (freedom of speech, even on a plane). Your employer can’t take your kidney because your contract says you must give one if you’re late to work even if giving away a kidney is legal. But you can still agree to give it if you want to.

If you have the same rights given by law then you can’t have any restrictions on those rights that aren’t in the law. Your rights have the same restrictions they always had and a contract can’t add a couple more. So you have your freedom of speech that a contract can’t take away, the law already defines the restrictions. But a restriction to smoke in the bathroom, which was never your right to begin with, is fine because the law never gave you the right to smoke in a plane bathroom.

You have your rights or you don’t. Calling this a technicality is a lame cop out.

Now you could argue (but you didn’t) that “broadcasting” the word “bomb” on a plane doesn’t constitute free speech. You’re not allowed to yell this at a concert either, it depends if broadcasting (not reading the BT spec to see who initiates the communication) a BT name and shouting are equivalent. But I can’t imagine saying “free X, screw Y” is anything but free speech for anyone not on Y’s payroll. A contract can’t put a restrictions on expressing opinions without them already existing in the law. Do you think there’s a law that says “free to state your opinion except on planes”?