Chess ELO is not a proxy for general intelligence because many intelligent people choose to learn things other than chess. But any intelligent person can, if they choose, learn chess and play it well.

LLMs cannot do this. They still play very poorly relative to human pros, and even modern LLMs still understand the rules so poorly that they request illegal moves.

Anyone claiming that we should be afraid of a text generator that can't understand the rules of chess is being ridiculous.