I think they meant "Nobody knows why LLMs work."

same thing? The how is not explainable. This is just pedantic. Nobody understands LLMs.

Because they encode statistical properties of the training corpus. You might not know why they work but plenty of people know why they work & understand the mechanics of approximating probability distributions w/ parametrized functions to sell it as a panacea for stupidity & the path to an automated & luxurious communist utopia.