@nimh,
It is possible to deprecate the Bernie or Bust crowd without being liable to being described as a Bernie hater. I don't like Sanders, and have not since he suddenly broke onto the scene, with a tail of hating supporters behind him. They pissed and moaned when they discovered they had to register as Democrats to vote in some primaries. FFS, if you're going to participate, it helps to know the rules. Keep in mind what Bernie or Bust actually means. I agree with Snood to that extent.
To put some perspective here, I have always blamed Mrs. Clinton for her ham-handed, lazy and seemingly direction-less campaign. She lost that election because she did it stupidly, and without any apparent plan. She still won the popular vote, which means nothing if you don't keep the Electoral College in mind, which doesn't seem to have been a part of her planning. At the same time, Bernie and his crew did little to help.
In almost all quadrennial contests, the hopeful candidate needs to keep an eye on the Electoral College, and to attract the "unaligned center," the voters who have not made up their minds and are not the devotées of either party. That's what will win in 2020, and Bernie or Bust won't help anyone, even if Sanders is the candidate. It's a big country with lots of different voters to draw in.