Hard policy, light enforcement in practice means there is an actual shadow policy that you don't know, which is pretty bad to the point that it would be illegal if the government did it.
Curious about your comment on two counts (genuinely, not being argumentative):
1. how is this bad, in Codeberg's case, practically speaking?
2. in what cases is this illegal for governments to do? In practice no legislation is perfectly enforced, & even judiciaries have varying degrees of exactness across countries - to the point that things such as desuetude are densely studied legal topics.
(note: I'm aware of the negative ramifications if desuetude but not aware of any negative ramifications of Codeberg's specific ai policy)
Governments have a lot of laws that they don't enforce, or enforce only lightly. For example, weed is still illegal in Netherland, despite many decades of tolerating its use.