To my knowledge, Business and Personal Mail (and email) are in a totally different catagory.  A business owner too, can use your mails to them and make them pubic if they are "blacklisting" you, for various reasons.

I think you are totally within your rights to disclose unprofessional behavior to a community that might use this person's services.  People do have a right to know who they are dealing with.

As for lible, I wonder if they would sue Consumer Reports too, if there was a bad article on them in there LOL.