Most humans also write plausible code.
Humans would execute that code and validate it. From plausible it'd becomes hey, it does this and this is what I want. LLMs skip that part, they really have no understanding other than the statistical patterns they infer from their training and they really don't need any for what they are.
What a shame your human reasoning and "true understanding" led you astray here.
It's better to describe what you can do that LLMs currently can't.
If they'd bother to see how modern neuroscience tries to explain human cognition they'd see it explained in terms that parallel modern ML. https://en.wikipedia.org/wiki/Predictive_coding
We only have theories for what intelligence even means, I wouldn't be surprised there are more similarities than differences between human minds and LLMs, fundamentally (prediction and error minimization)