You can read the 21-page opinion at this link. The key point from the judge is the view that counterspeech is a more narrowly tailored alternative to the regulation of political speech.
I agree with the lower court that California’s law is likely unconstitutional—mainly because of its treatment of “parody” and “satire” as different from other speech. However, the judge’s opinion here lacks naunce and recognition that a state mandatory labeling law for all AI-generated election content could well be constitutional. (I make this argument in some depth in by 2022 book, Cheap Speech). I fear that the judge’s meat-cleaver-rather-than-scalpel-approach, if upheld on appeal, will do some serious harm to laws that properly balance our need for fair elections with our need for robust free speech protection.