There is no consideration in the law whether he actually plans to use it or ever meant any violence, nor any consideration of whether it violates ITAR.

As someone who has a lot of interest in weapons law, this is probably about the only kind of weapon that can't be even legally contemplated in the USA, worst case for almost anything else you can get an NFA stamp. The USA is absolutely paranoid about yielding their air power so they come down like a ton of bricks against anyone that might want to defend against that.