Use of the passive voice allows propagandists to avoid attributing or taking responsibility for actions. "In the passive voice, the subject of the sentence is neither a do-er or a be-er, but is acted upon by some other agent or by something unnamed (The new policy was approved). In the active voice, the subject and verb relationship is straightforward: the subject is a be-er or a do-er and the verb moves the sentence along (The executive committee approved the new policy)." 
In propaganda, the passive voice sometimes masks arguments of authority. When the speaker does not declare who performed an act, there is often a veiled inference or ambiguity that rests solely on the authority of the speaker for a flawed logical foundation.