The problem is this CBG
1. They have access to top level registrar information. Even “private” registrations.
2. They know what domains you own.
3. They dont have to prove anything to anyone. If they get annoyed with you for any reason they can penalize ALL your domains no matter where they are and not serve them up in their serps.
They HAVE done this in the past and they continue to do it. If they believe you have too many domains on a given topic they make you vanish from their returns because they assume you are a “spammer”.