The line comes from Denis Brogniart, the French television presenter best known for hosting Koh-Lanta, and this particular excerpt is associated with a YouTube Poop edit called La finale irrévocable. In that context the phrase is lifted out of its original broadcast flow and turned into a standalone reaction, which is how it reached soundboards and short-form edits. Because c'est con is a common French expression for something stupid, the clip works even for viewers who do not know the show, and its sub-second length keeps it easy to reuse as a quick punchline.