Modern Earthlings don’t give credit to people that painted on rocks as potentially being satirical. They view history as a continuum of facts dictated by serious people. Say the apocalypse hits tomorrow. Everything is buried. Do you think future generations will be able to correctly analyze the difference between satire and “serious” art (whatever that means)? They’ll dig up thousands of Ronald McDonald and Burger King statues and make the assumption that we died in the war between the Clowns and the King. And they won’t be far off. But when you stuff your face with fast food, you don’t even think you’re in a civil war.
Then anthropologists will discover three newspapers: a New York Times, a National Enquirer, and The Onion. One is meant to be factual (supposedly), one is meant to shock, and one is meant to be humorous. But how will the non-English speaking anthropologists understand this? All three artifacts will be honored and studied as facts from the past.