Because they ask non-challenging questions or simple-minded ones. For example, Wildcat said a question, "What's better: cats or pandas?". The answer was cats...*facepalm*

If you're going to host a proper trivia event, avoid opinionated questions like what I mentioned above. There's very few on staff that actually make questions that are challenging and are already prepared with the theme of the trivia. Others are simply incompetent.