The Democratic capital-D primary is not a democratic lowercase-D process – it’s not supposed to represent the will of the people, it’s supposed to represent the will of Democrats. Consider Paul Krugman on Bernie Sanders’ tone following the commitment of superdelegates:

This is really depressing: Sanders claiming that there will be a contested convention, and suggesting that the nomination fight was rigged. Can someone tell Bernie that he’s in the process of blowing his own chance for a positive legacy?

It’s not depressing, it’s just half true. Bernie Sanders would have won New York in a general election, and if it was against Donald Trump it would have been by wider margins than Trump v. Clinton.

The pitch that Sanders has for superdelegates of the party is not “join me to represent the will of the Democratic capital-D voters”, it’s “join me if you want to win.”