Re: Wrong - it's pure blackmail accroding to US statutes
Except in the real world, no they didn't.
I presume you are referring to CNN threatening to dox the individual - correct me if I'm wrong.
I don't know about what the amendments do or do not say but how do you explain:
"CNN reserves the right to publish his identity should any of that change."
(Ref: http://edition.cnn.com/2017/07/04/politics/kfile-reddit-user-trump-tweet/index.html)