He didn't really explain the full problem so maybe I am not fully appreciating the situation here, but this seems like a pretty big overreaction for a stupid request from some a single user.
If I add one of the latest in the series of my own experiences. Once upon a time someone wanted to scam me on a website deal. We figured out who it was (it was easy, he was the owner of the domain, paid for the hosting etc.) and published the details (we were not the first, he's quite a known scammer around here, we found numerous blogposts about him). He was even featured in a local newspaper. Fast forward 5 or so years and I get a Cease and Desist letter from him (or something looking like that) that the information in my blog post is not accurate and he will sue me. I quickly see that google doesen't bring much about him nowadays, in part to people not caring for their blogs/doing redesigns and in part of him sending out "scary" letters. Of course I could fight it, I had a lot of concrete (I was told court grade by some lawyer acquaintances) proofs. But was it worth my time? My effort? My psych? No. I redacted the blog post and let it be. I don't feel good about it, because that means he will try to scam people that could'we been warned from my post. But I wagered it and left it all behind.
EDIT: grammar n'stuff