You've got it backwards. The judge in Silverman et al dismissed the claims asserting that OpenAIs output is copyright infringement. The claims for copyright infringement in the training data are still going forward, that will directly test whether it is "fair use" or not.
From the ruling:
> Assuming the truth of Plaintiffs’ allegations - that Defendants used Plaintiffs’ copyrighted works to train their language models for commercial profit - the Court concludes that Defendants’ conduct may constitute an unfair practice.6 Therefore, this portion of the UCL claim may proceed.
https://caselaw.findlaw.com/court/us-dis-crt-n-d-cal/1158180...