True, though you have to remember that threat is a social construct and isn't necessarily a rational measure. The 2001 anthrax attacks killed 5 people, injuring 17, and shocked the nation. As a direct result Congress put billions into funding for new vaccines and drugs and bio-terrorism preparedness. If 5 people were killed and 17 wounded in a mass shooting by a terrorist, would we really have reacted as strongly?

If you wanted to install fear into a country, I think being attacked by some custom, previously unknown chemical weapon would scarier than sarin.