True enough. But if you read the opinion, you will find that every time they refer to "disruption", they are always talking about it originating from the students wishing to express themselves. They make a very strong point about how "passive", "unaggressive", "pure speech" is to be protected.
Here's one telling passage:
"The school officials banned and sought to punish petitioners for a silent, passive expression of opinion, unaccompanied by any disorder or disturbance on the part of petitioners. There is here no evidence whatever of petitioners' interference, actual or nascent, with the schools' work or of collision with the rights of other students to be secure and to be let alone. Accordingly, this case does not concern speech or action that intrudes upon the work of the schools or the rights of other students."
It seems to me that it could be interpreted that as long as the students wearing the shirts were respectful and quiet, and not holding demonstrations or otherwise inciting the other students, that this type of speech would be protected. It would seem to me that if someone is offended by the speech and throws a fit over it, that's their problem. Otherwise, it'd be real easy to squelch free speech: See someone wearing something you disagree with? Then throw a fit & get them sent packing. Right? Do you really think that's what the court is trying to say?
as long as normal school functions are not "unreasonably" disrupted.
It was stronger than "unreasonably", as read from this passsage in the ruling:
"Certainly where there is no finding and no showing that engaging in the forbidden conduct would materially and substantially interfere with the requirements of appropriate discipline in the operation of the school," the prohibition cannot be sustained."
Exactly right. newgeezer is smoking wacky weed on this issue.