The only difference is that in the schools there are limits on those rights. As a teacher, I am here to tell you that dress codes need to be in place. I know at our school the kids are not allowed to wear t-shirts that advertise alcohol, tobacco, drugs, etc. nothing suggestive or "offensive" which opens the door to quite a lot of stuff. Schools are all about presentation and an atmosphere of learning. Like I tell my students, minors have more limits on their liberties than do their adult counterparts.
Oh, I totally agree with that. I think there needs to be a LOT of restrictions on what children wear to school. But even, then, you can't pick and choose. If the school has a policy saying that the confederate flag is offensive and can't be worn on clothing ... what about the Black Panther flag? If schools would prohibit t-shirts with ANY sayings or pictures at all on them, that would be great. But, even a school can't say this is ok, but this is not.