See elsewhere where I've quoted parts of it in this thread but if you read "Actually, I don't think Africa is polluted enough!" and take the person saying it seriously instead of reading it as a joke, then you might need to touch grass.
If Kevin Spacey had written a private note to Woody Allen that said, "Now that we've been chased out of the film industry, let's become day care workers," then it would be a very different kind of "joke" than The Onion writing the same as a headline.