I'm trying to find something in your explanations that doesn't warrant that conclusion, but I'm not having much luck. You've said you're only interested in discussing art as propaganda for evolution, but not as propaganda for anything else.
If you wish to discuss propaganda in general I’ll be glad to do so. My earlier comment was an attempt to stick to the article but since we’ve strayed a bit from that my objection is really invalid now.
What examples or sources of propaganda do have in mind?