I don't care
I know the wound is still fresh but obsessing on who or what to blame won't fix our problems. Next election cycle, saying or typing "GOTV" won't bring it home either.
These big majorities of Dem-leaning supporters are not going to help elect Warren as president in 2016.
The election laws are set. The congressional boundaries have been drawn. SCOTUS has spoken on the Civil Rights Act and CU. Based on the current congressional makeup, that isn't changing. If anything it will only get harder.
We have to fix it at the state level. Elect good, young Democrats to local and state offices. Have these Democrat state legislators change voting laws. Reshape congressional boundaries so they are more fair.
That is how we win elections going forward.