"Shame on him, who suspects illicit motivation" is given as one of the many possible translations. Don't take the "shame" part too literally, but there is some irony in pointing out someone as a troll when the one comment you use for doing so turns out to be true, and interesting to boot (Kasparov engaging in bad-loser-let's-warp-the-facts behavior).

I'm not taking a stance on the issue whether Thomas is or isn't a troll, you were probably mostly looking for a good-seeming place to share your opinion about him.

(Like spotting a cereal thief in a supermarket, day after day. Then when you finally hold him and call the authorities, it turns out that single time he didn't steal.)