To be objective I have to ask myself, is it not possible that false narratives could become a terror threat? It would seem to me there are situations that they could be. Not that I have such faith in the government but false narratives can be quite deadly.
Define terror threat. Then define false narratives.
Words can be characterized as "terroristic threats," but words are not terrorism.
Threats do not cause death, injury or destruction.
Threats that are determined to be credible and imminent can result in charges, but again, threats when void of action are just words.
A false narrative alone is not a threat -- terror-related or not.
The proper response to misinformation, false narratives and lies is open, honest and well-supported counter-narratives. When the truth is presented side-by-side with the lies, most people are able to pick out which is the lie.
Pretending we should treat words the same as acts of terror is why we have the 1st Amendment. The right to free speech is limited in that you can't communicate a real threat to a specific person or organization. But to speak out against that person or organization is protected -- even if it's false.
Anyone who's experienced actual terrorism would laugh if you told them words -- any words -- can be a terror threat.