Comment by cryptonector

> But why didn't Supreme Court find the first ammendment arguments compelling?

Read the decision. They thought the act was content-neutral, and they thought that the espionage concerns were sufficient to reach a decision w/o having to involve the First Amendment. Gorsuch and Sotomayor weren't quite so sure as to the First Amendment issues, but in any case all nine justices found that they could avoid reaching the First Amendment issues, so they did just that.