I also found the statement bizarre. They don’t seem to have any argument for compensation of any kind unless the books were under a restrictive license that required derived works to also be open source.
replyNo, even under such a restrictive license (which I think the GFDL is?) there's no argument.
replyThere copyright was not violated by anthropic downloading the books, because anthropic had a license to do that.
And there copyright was not violated by anthropic training on the books, because the court found that no ones copyright was violated by doing this. Antrhopic didn't need a license to do this. So the restrictive terms of the license can't prevent it.
I mean they might have an argument for compensation based on "well the settlement Anthropic agreed to didn't exclude us even though they didn't violate our copyright"... but just for the compensation outlined in the settlement.