I do tend to think that DU was specifically targeted.
I recall reading posts from (if I remember correctly) DUers in South Florida saying that they had been to the polls and the lines were way shorter than in even 2012. (Of course, there were other DUers saying not to worry because we had crushed them in early voting AND recall that the campaign was saying we had it in the bag). In other words, DUers were actively talking about there being early signs that our GOTV was failing to get turnout among vital voting blocs. This was not getting picked up at all in the national media. It was only being communicated through sites like DU. The fact is, for better or worse, DU has a ton of members who are, shall we say, "well-connected" at the national party level. IF they had known this was going on in real time (and that is what DU is, a source of real time information), we would have at least had the opportunity to pour GOTV resources into the Blue Wall and, given the closeness of the votes in those states, perhaps made a difference.
I know this sound paranoid, but if you look at Michigan, where polls closed when we still had no idea what was happening, our turnout was hundreds of thousands LOWER than in 2012. Then, when you look at California, where the polls closed with people knowing we were looking at a disaster, our turnout was over a million votes HIGHER than 2012.
I may just be making Reynolds shareholders wealthy, but you have to wonder.