There are two strategies described in this paper. The cyclic adversary, and the pass adversary. You are correct that the pass adversary is super dumb. It is essentially exploiting a loophole in a version of the rules that Katago doesn't actually support. This is such a silly attack that IMO the paper would be a lot more compelling if they had just left it out.
That said, the cyclic adversary is a legitimate weakness in Katago, and I found it quite impressive.
That said, the cyclic adversary is a legitimate weakness in Katago, and I found it quite impressive.