I should probably write a blog post about it. Basically it’s there to possibly get commercial LLMs in trouble for scraping licensed stuff. LLMs have been tricked into revealing their training data and gotten in trouble for that. There are also ongoing lawsuits due to those revelations. Maybe the most notable is the one against Github’s Microsoft’s CoPilot for spitting out licensed (GPL and also copyrighted from private repos) code.

Whether the lawsuits will be successful or not is yet to be determined (Japan already considers nearly everything fair game for training AIs and machine learning). Whether they will have an impact if they are successful is also unknown. It just costs me a key-stroke (and the occasional response to a friendly question like yours), so I do it 🤷 Once all my hope is lost, I might stop.

From another answer. I highlighted the important part, which explains why the explicit link to the license text instead of it being implicit.

Anti Commercial-AI license