What are you going to do about your naughty news poster

Unless they are doing something illegal, nothing.  Usenet is self-policing.  If one of our clients is doing something you don't like we suggest that you add them to your killfile or use some other accepted Usenet practice to handle their postings.  In particular we are not going to determine what is and is not on topic for any particular newsgroup.  With over 107,000 active newsgroups, we cannot be experts on the acceptable use for each one.