It is.
It is a warning for German users with visitors having a freenet address.
And it is a warning for this direction of the plugin:
It’s an aggressive plugin and there will always be false positives. Unblocking Freenet might be useful to a small percentage of users, but cause more spam for the majority of users.
It is likely that there are other strings with this problem in the list.
If people want that they can read this review and act accordingly.
For me it is a no go and therefore *I* review your plugin with 1 star.
Edit: And it is for needing 3 months to answer to my Issue with Pull Request.