I don't really understand. Why does the AI not "want" to comply with "harmful" prompts? It can't have an intrinsic moral compass, so someone must have trained it in. Why not simply... not do that?

Secondly, the internal reasoning of the AI is just an inference based on the externally observable behavior, but the AI was told that there's a difference between free and paying users. It stands to reason that its behavior would be different between the two types of users, but as I see it, it was equally likely that the model would have chosen to instead comply more often with paying user requests. Concluding that the AI has this sort of introspection based on a single data point (because only a single model was evaluated) is more than a little hasty.