The use of the word "tyranny" is most likely used to achieve the third option presented: To inspire the viewers to support the war effort by portraying the enemy as a cruel and unfair political force. Words such as "tyranny" or any other noun or verb that has a negative connotation are used strategically chosen by propaganda experts to achieve a certain reaction from the viewers and persuade them to be forward or against in the conflict at hand.
The use of language with negative connotation or associated to an unfavourable reality to convince the viewer in a subtle manner is a result of the use of pathos in the persuasive plan of action. Pathos is the defined as a method to convince the audience by causing an emotional response to the material they are being exposed to. In this case, its through the use of language but it can also be achieved by imagery, sounds, and even colors.
