This isn't what this issue is about. No one is claiming the kid had a right to stay anonymous, but according to https://www.justice.gov/crt/conspiracy-against-rights we do have protection against

...two or more persons conspire to injure, oppress, threaten, or intimidate any person in any State, Territory, Commonwealth, Possession, or District in the free exercise or enjoyment of any right or privilege secured to him by the Constitution or laws of the United States, or because of his having so exercised the same;...

Andrew Kaczynski and others at CNN threatened and intimidated u/HanAssholeSolo in the free exercise of his first amendment right of freedom of speech. It's pretty straight forward.

By definition:

Threat: a declaration of an intention or determination to inflict punishment, injury, etc., in retaliation for, or conditionally upon, some action or course

Intimidate: to force into or deter from some action by inducing fear

Kaczynski claimed to have doxxed the user and intended to exposed him publicly in retaliation for making a meme. That's a threat by definition. He then used this threat to force the user to issue a public apology and stated that if any further posts were made that Kaczynski didn't like, the user's information would be released at that time. That's intimidation by definition.

Andrew Kaczynski and his co-conspirators broke the law. It's that simple.