Unstated assumption is a type of propaganda

Propaganda

Propaganda is a form of communication that is aimed at influencing the attitude of a community toward some cause or position so as to benefit oneself or one's group....

message which forgoes explicitly communicating the propaganda's purpose and instead states ideas derived from it. This technique is used when a propaganda's main idea lacks credibility, and thus when mentioned directly will result in the audience recognizing its fallacy and nullifying the propaganda.