Heh. This from the guy who insists that the reason the Associated Press style guidelines decided to start capitalizing the racial descriptor “Black” has to be that they were forced into it by a “violent mob”.
Yeah, octopus, you’re not actually the most credible spokesperson for the position of “reasonable people can have valid reasons for disagreeing about a particular choice of speech”.
Ha HA ha ha ha HAA! I can tell you never encountered anyone who, say, went to school wearing long hair (if male) or an antiwar or pro-Soviet Union symbol back before such practices became fashionable. People who had those experiences report that, contrary to your assertion, performative outrage abounded.
No it isn’t. Not every potential sexual innuendo or depiction of alcohol counts as advertising or obscenity or child pornography, for example.
The school’s dress code as quoted in the OP already includes very sweeping bans on various subjects of speech that don’t fall into the categories you cite as having limited First Amendment protection. So your attempt to argue that the school is just following a clear bright-line distinction between stuff that’s protected by the First Amendment and stuff that isn’t is not at all persuasive.