What makes one "deceptive propaganda" and the other "merely an illustration"?
In one form or another you’re asking the same question over and again. And I think you’re getting basically the same answers even if they’re not satisfactory to you. Sorry.
“What makes one “deceptive propaganda” and the other “merely an illustration”?”
I’ve given the best answer I can already.
“How are the details of what dinosaurs looked like any more speculative that the details of what Noah’s Ark looked like?”
Wouldn’t the answer depend upon the particular example?