Banning "AI" is too broad and too shortsighted.
They haven't done that. The actual terms are
You must not share projects that mostly consist of code written by "generative AI"-tools (including services such as Claude, OpenAI Codex). Such projects having an unclear copyright status (see requirements § 2 (1) 1 and § 2 (1) 3) and furthermore have little safeguards to ensure that they do not include harmful code (c.f. § 2 (1) 5).
See also their blog post, where they specifically mentions experiments as "tolerated":
Side projects and experiments with little resource usage