What exactly do you think the primaries are? They are not official elections. The democratic party (and the republican party) exist to help the candidates they want to support get elected. Note the mere existence of superdelegates. Primaries are designed to allow people to have some influence on the party's choice (and to get the electorate feeling invested in the party's choice of candidate... obviously the DNC messed that up), but really, the primaries are designed to maximize exposure for the candidates to help them in the general election. Trump is the perfect example of why the parties want some control over who they lend their name to in the general election. I'm sure that the emails flying around the RNC while they had a chance of influencing Trump's election put the DNC to absolute shame.
Bernie was not even a democrat at all prior to this election. Bernie has been an independent for his whole political career. He joined the democratic party just for this election, and he's now an independent again. It seems absurd to expect party support with that context. I think Bernie made a deliberate choice to run in the Democratic primary (despite not being a Democrat) to avoid the spoiler effect in the general election, knowing that it was unlikely he would get DNC support. I respect him a lot for that decision.
Don't get me wrong, I would have been very happy if Bernie won (especially over Trump), but this idea that the DNC is a rotten institution that deserves an organizational death penalty for working with Clinton over Bernie is ridiculous.