You do not seem to get it. Yes, I understand that if fair use applies, my licenses don't matter. I get that. I promise I do get that.
The purpose of these licenses is to sow doubt that fair use applies to distributing the output of ML models.
Lawyers are usually a cautious lot. If a legal question has not been answered, they usually want to stay away from any possibility of legal risk regarding that question.
The licenses create a question: does fair use apply to the output of ML algorithms? With that question not answered, lawyers and their companies might elect to stay away from ML models trained with my code, and ML companies might stay away from training ML models on my code in the first place.
That is what I mean by "poisoning the well." The poison is doubt about the legality of distributing the output of ML models, and it is meant to put a damper on enthusiasm for code being used to train ML models, especially for my code.