Prior Restrain is totally valid in the US and there are many many circumstances where it can be used. Try breaking a gag order, or tweeting your location while fighting in Iraq. Or quit the NSA and start revealing secrets. This whole idea anyone can say anything is simply not true, and frankly shouldn't be true. Some facts are very very dangerous.

I certainly don't want simple plants for bomb making out on the internet.... I'll happily give up certain rights for that.

You probably shouldn't make any arguments about free speech based on whether or not a soldier can say something. You sign a lot of papers and give up a lot of rights when you volunteer to serve or get a security clearance.

Soldier, or whoever. It is totally unwarranted to put our forces in harms way whoever you are and such speech is certainly not protected regardless of who you are.