First -- it's a crime, plain and simple. Somebody should go to jail. Sites trafficking in stolen goods should be charged.
Second -- glad it happened in September. Can you imagine something like this happening, only in the last week of the election? Heck, you could put any kind of flamebait stuff you wanted in the screen shots. It doesn't even have to be real. It could easily throw the election and you're left with a mess and nobody to blame for it.
Third -- How was the system breached?
This is definitely hacker news. As an example, I had an idea last year for a site/app to keep track of breaking election-year news. As the emotional juices roil in the 40% of die-hards on each side, there's this incredible thirst for up-to-the-date, cutting-edge news and insights. It doesn't get much more up-to-date and insightful than reading the candidate's email. (Note earlier comment about legality, though)
Where there's a great thirst, somebody is going to be selling trips to the water fountain. Not only is there lots of money in this right now, elections are predictable, repeatable events and piggybacking on people's emotional investment in them is only going to get more and more profitable.