I do use and run my own LLMs locally. But I understand why Debian might ban it, under just 1 reason:

LLM outputs cannot be copyrighted.

That alone starts to invalidate the GPL and other FLOSS licenses. It overall weakens the project the more you accept. And companies (MS, Amazon, etm) will gleefully loot anything marked with "LLM" as a free-for-all.

Until the whole copyright situation can be finalized, I'd understand for any FLOSS org to refuse all LLM code.

(Its also the same reason why Oracle also forbids all LLM code in Java and their DB. Same reason.)

There's not yet any reason to believe that mixing LLM output with your work makes it uncopyrightable any more than hitting enter in intellisense did before that.