Perhaps it makes no sense to discuss the truth value of propaganda, but I don't really see a huge diff between the examples given.
[WS:] Joanna, the point is not the truth value of propaganda, but its treatment of the audience. Every good propaganda is fundamentally true when taken literally, only bad and inept propaganda uses outright lies and falsehoods. If there is a falsification element in propaganda, it is by selective omissions, emphases, and taking things out of context. But hey, most of literary analysis does that to some extent, so it is not the greatest sin in the world.
The main sin of propaganda is its treatment of the audience, or more precisely, the implied relationship between the speaker and the audience. In the ordinary discourse, this relationship is a dialogue, even if the parties are unequal in terms of the information they have. The speaker provides that missing information with the implicit assumption that the audience is capable of interpreting it on it sown and provide the speaker with a feedback. So the end result is some form of dialectical synthesis between information conveyed by the speaker and the interpretations and feedbacks from the audience.
In the propagandistic discourse, by contrast, the speaker is assumed to have moral superiority over the audience and be right by definition. The purpose of the communication is to have the audience accept both, the message and the speaker's interpretation of it. No feedback is needed, and if that feedback differs from the expected interpretation - it is being viewed as subversive to the communicative act itself. What is more, the speaker treats the truth function of his speech purely instrumentally - its sole purpose is to bypass the critical defenses of the audience and have it accepted the speaker's stance "as is" - rather than to inform the audience and develop a shared understanding of the situation.
In other words, it is not about the contents but about the intentions and communicative style. My problem with the propagandistic discourse of the Left (or any propagandistic discourse for that matter) is not that what it says is false (albeit not free of omissions and selective emphases, but that is a different story), but that it is overly moralistic and holier-than-thou toward its audience, as reflected in its choice of verbiage and liberal use of hyperboles. Its main purpose is to establish the moral superiority of the speaker over the audience by shaming or guilt-tripping the latter while taking a rigid, uncompromising position projecting "self-less ideological purity" by the former. Each time the audience refuses to be shamed or guilt-tripped and accept the moral superiority of the speaker, it is automatically treated like a bunch of uninformed morons or subversives.
It is very difficult to rebuff propagandistic discourse, because by definition it is not a dialog between equals. Any bona fide challenge is automatically dismissed as ignorance or malevolence. The only effective way of combating it is to ridicule the speaker, or perhaps provoke him to make an idiot of himself, because it effectively deprives him of what he wants - moral or intellectual authority. The latter may be difficult with seasoned hack propagandists, but poking fun and ridicule is always an option.
Wojtek