This can be true only in #3World, using a definition of "slander" from the #3LegalDictionary.
Perhaps your tax lawyer will explain the real world meaning of the word "slander" to you.
If he behaves anything like his persona on this forum one may easily predict the following scenario: The tax lawyer will try in vain to correct his definition, but he'll probably respond by calling the poor guy names and telling the lawyer that his understanding of the law is wrong. When the lawyer tries to leave he will continue following the guy out the door and down the street while berating him with subsequent insults and attempting to bait him into further conversation.
His partner will know all about it.