Yes, it was part of the hack. I was lucky enough to be perusing DU when it happened, and knew right away what was going on. Twas a glorious, glorious time! 
So, DU actually WAS hacked?
I was under the impression that Skinner simply took the site down because he knew as the election leaned more and more towards Trump, enraged DUmmies would post multiple threads calling for Trump's assassination, and didn't want to be visited by the FBI, so he took down the site for a while and claimed it had been hacked.