It has no idea about the quality of it's data. "Act like x" prompts are no substitute for actual reasoning and deterministic computation which clearly chess requires.
The blog post demonstrates that a LLM plays chess at a decent level.
The blog post explains why. It addresses the issue of data quality.
I don't understand what point you thought you were making. Regardless of where you stand, the blog post showcases a surprising result.
You stress your prior unfounded belief, you were presented with data that proves it wrong, and your reaction was to post a comment with a thinly veiled accusation of people not being educated when clearly you are the one that's off.
To make matters worse, this topic is also about curiosity. Which has a strong link with intelligence and education. And you are here criticizing others on those grounds in spite of showing your defitic right at the first sentence.
This blog post was a great read. Very surprising, engaging, and thought provoking.
That conspiracy theory holds no traction in reality. This blog post is so far the only reference to using LLMs to play chess. The "closed-source" model (whatever that is) is an older version that does worse than the newer version. If your conspiracy theory had any bearing in reality how come this fictional "real chess engine" was only used in a single release? Unbelievable.
Back in reality, it is well known that newer models that are made available to the public are adapted to business needs by constraining their capabilities and limit liability.