The entire purpose of the modern political machine is to take your general discontent and channel it toward individual people, in this case Bush II, so that you will forget the true scope of your oppressors.
Gore, having lost, gets to go down as the better world that could have been. Obama, having won the position of being salesman for the status quo, gets labeled the disappointment. But you'll have forgotten this in 4 years, when it is pressingly important that $REPUBLICRAT not be reelected.
Because one reason why Sanders was right to run as a Democrat rather than as an independent is that running as an independent might have enabled a Republican victory that wouldn't otherwise have happened, in which case Sanders's hypothetical independent campaign might be responsible for making Trump or Cruz president, which Sanders probably doesn't want.
Right? I really don't like that point of view, because it gives the incumbent power structures a legitimacy they don't deserve. I think it is folly to criticize dissenters for dissenting too hard instead of falling in line. The lesser of two evils is still evil. It is not right to judge someone negatively for rejecting two choices they find unacceptable.
Ralph Nader and Bernie Sanders are not responsible for the flaws of the system they choose to operate inside or outside of.
The irony is that Nader does not even admit his culpability in this equation. Leaving aside the disastrous Bush v Gore thing, Nader destroyed the Green Party's chance at creating a 3rd party movement that could have born fruit about now. He took all of the money that the Greens had socked away for their bottom up strategy, and set back 3rd party aspirations by 20 years.