Debian is its own project with their own maintainers and policy.

This would not conflict with linux kernel policy, nor with other upstream use of AI. The article makes it clear:

Importantly, the ban would not apply to upstream projects that use AI, software related to artificial intelligence, or patches and security fixes from upstream sources. In other words, Debian could still package third-party software developed with AI assistance, but Debian contributors would be prohibited from using such tools for direct project work

I would assume they would concider the kernel an upstream project and therefore exempt from the policy.