It’s a bit more nuanced than that. Chess engines exist, and computers have the ability to always make the most correct move given the current board state 100% of the time, even when viable alternatives exist. That’s how they tend to catch cheaters. If you’re out of book moves and making engine optimal moves every turn, there’s a strong suspicion that you are using a computer to cheat. Even Grandmasters play sub-optimal moves, so when novices come out swinging with near-100% accuracy on their scorecard, it raises a lot of alarm bells.
They merely stated his play was, across many games, indistinguishable from a cheater, they didn’t have actual hard proof that he was cheating.
If they had actual proof they wouldn’t have needed to settle
In chess, doesn’t that mean he was playing well?
It’s a bit more nuanced than that. Chess engines exist, and computers have the ability to always make the most correct move given the current board state 100% of the time, even when viable alternatives exist. That’s how they tend to catch cheaters. If you’re out of book moves and making engine optimal moves every turn, there’s a strong suspicion that you are using a computer to cheat. Even Grandmasters play sub-optimal moves, so when novices come out swinging with near-100% accuracy on their scorecard, it raises a lot of alarm bells.