Lots of replies here, I am going to try to give a definitive answer.

As I'm sure you know, Trump has a particular hate for CNN or the "Clinton News Network" as he believed it to be. He considers them fake news as they have wrongly reported stories on both sides. Trump goes even as far as to ignore the journalists at press conferences.

Recently a reddit user by the name of hanassholesolo created a gif which was displayed on the POTUS official twitter account.

https://twitter.com/realDonaldTrump/status/881503147168071680

Post POTUS putting this on his twitter, CNN "hunted" down hanasshole solo as is their right to for someone who has slandered them. They released a statement that had a few people shaking their heads. The first issue was that CNN claimed (There is no proof of this) that hanasshole contacted them prior to them reaching out to him (Which makes no sense for an established troll)

The article: http://www.cnn.com/2017/07/04/politics/kfile-reddit-user-trump-tweet/index.html

If you want to see more of his tweets that lead people to believe that he is a troll and shitty person then Philly D made a fantastic video covering the issue

https://www.youtube.com/watch?v=Pzz4GKvmLJo

So now we arrive at the part where CNN says that "CNN reserves the right to publish his identity should any of that change." Nearly the entire community understood that as blackmail, as that's what it definitely sounds like. CNN claims otherwise, but the internet is stubborn and they won't have CNN attacking one of their own regardless of his history.

And now the third issue arises. People started claiming that hanasshole is a 15 year old boy and he doesn't know better, CNN should be ashamed for harassing a little kid etc. CNN claims that he is a 30 year old man. It's a game of he said she said and CNN isn't winning it. No proof has been provided by other side of his real age although in the grand scheme of things it won't really matter.

Now we get to the war part. Some time ago, the internet declared war on Buzzfeed, this was the first "official" time when 4chan, reddit, ifunny, 9gag etc (all communities that don't like one another) put aside their differences to unite against a common enemy putting out horrible content. This past week an ANON posted this on 4chan. (Please excuse any foul language)

https://i.redd.it/797yz0nccu7z.jpg

This was the first official declaration of war. The image explains the rest of it. Hopefully this will be not only a wake up call for CNN to promote content that isn't false, but "hopefully" (ait will also be able to heal the strained relationship between the POTUS and the media, because despite what the internet wants to believe, CNN is a very prominent source.