The line comes from Vilebrequin, a French automotive YouTube channel built around car tests, project builds and deliberately blunt humour. C'est de la merde is a common French expression meaning something is rubbish, and in this context it works as a quick verdict rather than a detailed review. Short excerpts from car videos travel easily in reaction edits, memes and Discord chats, where a one-second dismissal is more useful than a long explanation. Its staying power comes from that simplicity: anyone who follows car culture instantly understands the judgement, even without knowing the original video.