I would softly disagree with this. Technically, we also understand exactly what a LLM does, we can analyze every instruction that is executed. Nothing is hidden from us. We don't always know what the outcome will be; but, we also don't always know what the outcome will be in rule-based models, if we make the chain of logic too deep to reliably predict. There is a difference, but it is on a spectrum. In other words, explicit code may help but it does not guarantee understanding, because nothing does and nothing can.