....the trouble with restricting any form of speech is that the people in power determine what's restricted.
That isn't true in the US. It's the courts that determine whether freedom of speech has to be restricted by some other vital interest. While the courts can be, in effect, controlled by judicial appointments, etc., the judges still have to operate within legal principles.
Weighing the right to free speech against other more important interests is nothing new and has gone on for decades.
You only have to substitute racial or anti-Semitic lor obscene pedophilic language or whatever for the anti-gay language on the tee shirt to see the wisdom of the court's decision.

