Hi,
For the record, you are right!
In the US you can be sued for anything. That does not mean that you will win. I have been threatened with suits over publishing certain poems. The person objected to the fact that they could be recognized, even though they werr not mentioned by name. They were in California, which has a damn tough law. If you sue for defamation and lose, you are liabel for all costs of the winning side, PLUS damages. T%his happened to someone that I know. He had a great case, brought it. HE should have won. HE lost. Had to pay all court costs and $50,000 in damages to the person that had defamed him.
My point is that even though you can sue anyone, you have to win and there can be dire consequences for bringing suits that have little or no merit.
For the record, I scrapped the book that I was being threatened over and replaced it with another book by the same poet. The risk was not worth it. I hate the idea of anyone telling me what to do, but the idea that I could lose my house over publishing a book that would make me less that $500 was not worth the risk.
Best,
Bill