Maybe, but it seemed simple enough. It still comes down to declaring it to be either illustation or propaganda.
The only thing your explanation does is remove any responsibily for making that determination from the viewer. Whatever they decide it's illustation or propaganda must be because that's how the artist intended it.
If the former can a generalized interpretation be predicted so that an artist could choose certain imagery with the hope of producing that interpretation effectively?
If the latter, can we, in the absence of a clearly stated objective by an artist, discern his motive, message, etc., apart from just examining the image, by examining the artist and the circumstances of his work?
As a corollary, If all interpretation is apart from the mind of the artist then can propaganda actually exist except in the mind of the artist? It seems the artist could not know how to make his message broad enough to reach a necessary majority of the viewers to actually produce propaganda or project some opinion if the probabilities of interpretation were infinite on the part of the viewer.
I realize this is a vast oversimplification but if it works why not?
If specific examples are needed the two greatest sources of propaganda that are easily shown in the visual, is art and advertising, even allowing for the overlap between the two.
I would suggest some study of those two as it can be easily and inexpensively done.