There are a number of technological misrepresentations in your quotation that would seem inconsequential to the average judge or journalist, but actually make a huge difference in meaning and effect:

...used his Facebook account...to design a web page...

The word "design" implies stronger intent and effort than is actually required to post an event to Facebook. "Web page" is not typically used to refer to user-generated content on Facebook, but rather a distinct presence on the Internet that exists independently of and can be accessed without assistance from Facebook. Saying "web page" rather than "Facebook post" implies a much wider intended exposure than is actually likely.

His message was distributed to 400 Facebook contacts...

This number dropping seems like a journalistic scare tactic. Probably half or more of the users on Facebook have hundreds of Facebook "friends." Saying the message "was distributed to 400...contacts" implies deliberate, intended dissemination of the post. It is far more likely that the post simply ended up in his news feed automatically, and that many of his 400 friends didn't even see the post. It is also possible that he invited all of his Facebook friends to the event, in which case all 400 would receive the invitation, but that is far, far different from, say, distributing a crime-inciting newsletter to 400 willing subscribers, or sending instructions to an active criminal network of 400 members.

So the guy posted a Facebook event, inviting people to the riots. Humorous, funny, probably took all of three minutes to accomplish, no harm done, four years in prison.

Meanwhile the banksters who have stolen billions from the public treasury have not even been charged, and won't be.