CNN behaved appropriately. This man (yes, Trump Jr. said a 15 year old boy, but he lied, it's a grown man) threatened violence and made anti-Semitic attacks against CNN staff members. He has a long history of racist, anti-Semitic, homophobic and violent verbiage. Because of him, there are CNN staffers who had to move their families as their children are receiving death threats. The man said he is sorry so CNN said, basically, OK, if you really regret your actions you don't repeat them. If you do, we will show who you are.
Obviously this man is stupider than Russian hackers. He did not really try very hard to hide his identity.
I know any attack on "fake media" (defined as anyone who does not praise Trump) is fine with some.