I was wondering about the anti-SLAPP as well, but put it off to some lawyer seeing an angle I as a layman hadn't read about. I imagine it may well be a novel angle, but it could still be a viable one, no way to know until it goes thru the process. Meanwhile, glad I'm not the only one for whom that triggered question-marks.
Meanwhile, it wasn't /that/ long ago that everybody said the GPLv2 had never been proven in court, but it has been now, and came thru with flying colors. AFAIK it's generally accepted, now.
I guess it's the turn of the relatively free subset of the CC-*s, now. Hopefully it comes thru too. However, it's my impression that the "without this licence you don't have the right to distribute at all, so you can't challenge the license or you lose your right to distribute all together" aspect isn't as strong with the CCs, which might leave them in a bit weaker position. Regardless, it'll be interesting to see how this legal experiment in the public commons turns out, for sure.