Let's say a student wore a shirt in a New York school that said "I✡️JQ", and the school principal ordered him to stop wearing it because it was offensive and he complied. But later came back with a shirt that said "Made in the USA With technology engineered in Europe" and refused to stop wearing it and was suspended, can get an injunction against the school to protect his freedom of expression?
Option 1 is that this is a private school. The school can establish whatever rules they want. There might be a cause of action for breach of contract, but more likely there is some clause saying "You have to do what the principal tells you". Private organizations are allowed to completely suppress you freedom of expression. Option 2 is that this is a public school, in which case they are bound by the First Amendment (which is a limit on government action). Such a prohibition is legally untenable, but you may have to go to court to get an official ruling on the matter. If speech is objectively disruptive, it can be limited, but your examples are not objectively offensive or disruptive, they are simply somewhat provocative. Here is a summary from the ACLU of what public schools can't do w.r.t. student appearance.
Im no legal expert but I will say this...
Even in public schools, there is a dress code. No gang symbols, modesty, etc. If youre distracting students with your "speech" then youre not helping the educational environment. Generally I think bringing divisive politics into an academic or job setting is grossly unprofessional and irresponsible, a petty cry for attention. I think you are there to learn, but if youre there to preach then youre not interested in learning. And youre not interested in learning that you could be wrong. I think speech is protected by the Constitution, but only protects you from the federal government... not from state or local government (unless repeated by the state constitution), nor from principles or school dress codes. Even as an entity funded by the federal government, public schools are not government bodies, principles are not federal employees, and the purpose of the school is to create an environment conducive to education for all students. More over legal protections arent really applicable since there is no real criminal punitive measure for disobedience; all punishments are administrative. Any form of propaganda (including indoctrination from teachers) should be removed from campuses. I think there is a time and a place for speech that doesnt have to be worn on ones person during the entire academic day. I think speech requires the written and spoken word, open debate and a willingness to have a rational, civil, and cogent dialogue... and cannot and should not be construed for all forms of one-sided expression. Nor is your willingness to do any of that indicated by turning your body into a bulletin board for a slogan. A debate is not welcomed by those unwilling to engage (but they equally cannot avoid being confronted - ergo youre being deliberately antagonistic), nor is it welcomed as a matter of practical use of the teachers and students time for curricula. I think that students who deliberately and repeatedly disrupt the classroom should expect expulsion as a worst case scenario, and I think the school would be well within their legal right. I think that as a minor, especially, ones rights - even constitutional rights - are rightfully limited. If you cant vote at 16, what makes you think you have a legitimate right to free speech inside a public classroom during school hours?