in the west we use different terminologies. Conspiration theorist, lunatic, danger for the nation, terrorist, extremist, anti semite, molester.
it depends on the profile of the individual, it makes it more believable than a generic "foreign agent".
Those all just sound like descriptions of terrible people, regardless of the government. No doublethink involved here
if the accused people in fact are, sure. and surely too many terrible people in fact deserve the accusation, but many don't, too many were/are characterised as such purely because they disagree publicly with official views on certain events.
If Snowden is some "terrible people" then ok I'm also a bad one and deserve the conspiracy theorist hat. Except that I disagree with the government's characterisation of Snowden (in his case danger for the nation) hence even also risk to be called something in the list, whatever fit my profile best.
When US government starts an official register of "terrorists", adding to it literally everyone who does not agree with its official position, we can talk about the word being similar to "foreign agent".