Ok, well to quote the opinion:
"We admit that, in many places and in ordinary times, the defendants, in saying all that was said in the circular, would have been within their constitutional rights. But the character of every act depends upon the circumstances in which it is done. Aikens v. Wisconsin, 195 U.S. 194, 205, 206. The most stringent protection of free speech would not protect a man in falsely shouting fire in a theatre and causing a panic. It does not even protect a man from an injunction against uttering words that may have all the effect of force. Gompers v. Bucks Stove & Range Co., 221 U.S. 418, 439. The question in every case is whether the words used are used in such circumstances and are of such a nature as to create a clear and present danger that they will bring about the substantive evils that Congress has a right to prevent. It is a question of proximity and degree."
This, combined with the fact that the ruling banned the pamphlet, i.e. restricted free speech, would seem to belie what you're saying.