[jMyles]

At a high level, the answer is something like "yes" - people who are not US Nationals who engage in protected speech in a region subject to police power of the United States have essentially the same protections as citizens or permanent residents.

At a lower level, the answer gets close to "no" - I suspect that, in cases like this, something in the ballpark of Kleindienst v. Mandel will be controlling in the eyes of SCOTUS, so no.

But even if this particular matter is not specifically regarded as protected speech under the 1st amendment by US Courts, it is still a free speech issue in general terms. This person's basic human right of expression has been abridged by the act of a foreign state and a spineless and compliant corporation.