Interestingly, a lot of Chipmixer clone pages still exist, and were not part of this investigation. one might think that it is a selective fight against the illegal use of mixing services, But this is not correct (I guess).
To what extent are these clone sites not scam? They must all be...

This is already another type of department that deals with these cases. That as long as they don't receive complaints they shouldn't do much.
If they're not scam, it's like @LeGaulois commented, they're not big enough for them to spend time investigating. They will just be monitoring and nothing more.