First of all the DNC is setup with Super Delegates to basically allow selected people inside the democratic party to have much more power than regular voters during the nomination for this very reason, they do not want the party high jacked by a disguised 3rd party candidate, to think they do not coordinate between super delegates would be naive, but it still does not make it impossible for a candidate not selected by the super delegates to win, they would just have to win by a very big margin. We saw the republican party come out loud and clear about trying to get rid of Trump before he won the nomination, they did the same thing the DNC was doing but out loud.
But the real issue here is, that if you hacked every politicians email account in the USA I think you would have a really good chance to find the same or way worse than anything that Wikileaks has released, regardless of what party you are for, you got to admit something is not right when one side has all the internal conversations released and the other does not. You are always going to find things like this if you try hard enough, I am sure both parties say negative things about the other side and even its own followers behind closed doors. If they had found some kind of smoking gun and wanted to release it, I am fine with that, but what they released and the way they released it, to me seemed like they were just trying to sway peoples minds more than do justice.