There are plenty of legal restrictions on free speech. Defamation, for example. We don't consider it laws against defamation to be tyranny, but rather legitimate acts of governance.
Moreover, the case in question did not involve an act of Congress, or in fact any express act of governance at all. There's a difference between being legally or illegally compelled by the government and simply being contacted by a government official. The government has freedom of speech, too, and they are allowed to express concern about dissemination of materials counter to the public interest.
Moreover, the case in question did not involve an act of Congress, or in fact any express act of governance at all. There's a difference between being legally or illegally compelled by the government and simply being contacted by a government official. The government has freedom of speech, too, and they are allowed to express concern about dissemination of materials counter to the public interest.