Because there is no "I don't know" in the training data. Can you imagine a forum...

		justsomehnguy 4 months ago \| parent \| context \| favorite \| on: Low-background Steel: content without AI contamina... Because there is no "I don't know" in the training data. Can you imagine a forum where in the response for a question of some obscure easter egg there are hunddeds of "I don't know"?

You gave one explanation, but the problem remains.