The supposed claim wasn’t that it could be used for piracy (despite many here parroting that claim), but that they advertise that it could be. I haven’t read the actual claim, but it seems they’re basing their argument on a block of test code that uses a video containing RIAA copyrighted music. It’s sketchy at best, but there’s a reason BitTorrent clients make no mention of piracy sites at all; The MPAA and RIAA are extremely litigious and will use any opportunity they get.
Perhaps bittorrent clients don't mention specific sites but there's no end of related projects that do, e.g. expand the three "Supported ___ Trackers" lists on https://github.com/Jackett/Jackett
I'm not aware of any notices filed against that specific project.