Harassment isn't. One of the big points of the article is that when law enforcement doesn't act that is justification that the action is legal and thus "free speech". Except that law enforcement almost never acts against online harassment. There are plenty of laws restricting free speech when it harms others, and I'd hope you agree that some of the examples in the article crosses the boundary into things that should be criminal.
The boundaries of harassment are very blurry and tend to favour the powerful. For example, some of the campaigns against online harassers look even more like harassment than the actions they're going after people for: http://www.spiked-online.com/newsite/article/online-trolls-w... Except that because it's the press harassing people to the point of suicide, we don't see anything wrong with it.
Not entirely true - the reaction in the UK to this whole incident has been quite negative from what I've seen. Then again, we're not overly happy with our press at the best of times...
The parent wasn't a comment about the article directly, but on a thread that was discussing acceptance or rejection of subreddits for "domestic abuse and snuff". I don't know that these constitute "online harassment".
