You have more faith in the US government than I do. I could see them finding out that there exists, for example, a campaign by global adversaries to spread vaccine misinformation. It's an easy step for them to start gathering and investigating all anti-vaccine posts with a certain size following on social media networks whether they are posted by a US citizen or not, in order to determine if they are related. Sure, the military can't act against US citizens directly, but they could easily hand them off to the FBI, who can.

I'll wait and see, though, I guess. It will be interesting to see what "misinformation" they decide to go after first. It's not liking choosing their target could be easily abused or anything.