2012-06-23
Explanation
The comic is titled "Funtime Activity #179,256: Infiltrating Other People's Protests." It shows a group of protesters, with a man in the center holding a large sign that reads: "It's Adam and Eve propagating the human race through incest, not Adam and Steve propagating the human race through incest." On either side of him are other protesters holding signs like "It's a sin" -- markers of a typical anti-gay-marriage demonstration.
The humor comes from the infiltrator's sign, which takes the well-known anti-gay slogan "It's Adam and Eve, not Adam and Steve" and extends it to its logical (and uncomfortable) conclusion. If you take the Genesis creation story literally, then all of humanity descended from Adam and Eve's children, who would have had to reproduce with each other -- making incest a foundational part of the narrative. The sign "agrees" with the protesters' basic framework while highlighting an aspect of the story that its proponents typically prefer not to examine. The comic satirizes the selective literalism often employed in culture-war arguments by making the subtext painfully explicit, all under the playful framing of it being a recreational hobby to troll protesters with their own logic.