‘death to america’ is a hyperbolic idiom meaning an end to american imperial dominance ...
To your point, I've heard this meaning before, although I don't think it is commonly known to the general populace (which is also to your other point about propogandization).
Potentially against your point, if a slogan/idiom is being intentionally misused for misinformation, it might be time to move to a different phrase, rather than sticking with the corrupted one. Additionally, if multiple phrases could be utilized, it may get the point across better (less likely to successfully propagandize multiple options, than a single option). Although, I suspect propagandists would weaponize the 'weakest' commonly utilized option against the cause.