But LLMs specialize in language, not in getting facts right or wrong. That's why they "hallucinate" – or BS – giving you wrong information in beautifully phrased sentences, sounding as confident as a news anchor.

Language is a collection of weird gray areas where there's rarely an answer that's 100% right or wrong – so LLMs are typically trained using reinforcement learning with human feedback. That is, humans pick which answers sound closer to the kind of answer they were wanting. But facts, and exams, and coding – these things do have a clear success/fail condition; either you got it right, or you didn't.