I loved this film
Certainly naive and misguided, but when you watch films you should see them through the glasses of their times and the information that was then available. Furthermore I don't think there were any direct lies in this film. The mock trials were shown as stilted, and with our current knowledge we can actually see that these people are lying, which was quite surprising. And objections were raised by characters in the film. The validity of the trial was never proclaimed by the film, only it's main character. And in fact everything we see is what he saw, we have no reason to believe the abmassador was lying.
I did not take offense at the misguided notions, and think it should rather serve as a warning. Fuurthermore the most important claim in this film - That Russia was an allie against Hitler, an allie that could defend himself and an allie we could work with - was true.
As for propaganda, I got to say that like most silent fans I'm a huge fan of Soviet Propaganda, often more for it's cinematic techniques than the actual meaning of the story, but never the less we still love these works today. This film is obviously not experimental in nature, like the early soviet films were, but it's still a beautifully made film with great performances and an entertaining and climatic tale. I can understand that many people are revolted at the naive presentation, but I think we should distance ourselves from such thoughts when judging a film on it's actual merits. And at this point in time this was what we knew.
My 1000 favorite films - http://www.imdb.com/list/PkAV7BgvMJg