LLMs are trained based on a zillion pieces of text; each of which was written by some human for some reason. Some bits were novels, some were blog posts, some were Wikipedia entries, some were political platforms, some were cover letters for job applications.

They're prompted to complete a piece of text that is basically an ongoing role-playing session; where the LLM mostly plays the part of "helpful AI personality" and the human mostly plays the part of "inquisitive human". However, it's all mediated over text, just like in a classic Turing test.

Some of the original texts the LLMs were trained on were role-playing sessions.

Some of those role-playing sessions involved people pretending to be AIs.

Or catgirls, wolf-boys, elves, or ponies.

The LLM is not trying to answer your questions.

The LLM is trying to write its part of an ongoing Internet RP session, in which a human is asking an AI some questions.