The DNC can make decisions about future primaries—in direct consultation with the CDC—if it believes upcoming votes could endanger public health. But *every* Democrat, no matter who you support, is bound by (and should feel bound by) the rules all Democratic candidates agreed to.
PS/ I believe—Gabbard excepted—that if any candidate in the race, e.g. Sanders, should come to the conclusion that he can't win the nomination, he'll act accordingly. Clyburn's words aren't helpful to party unity—and you should find that especially so if you're a Biden supporter.
PS2/ If you're a Biden supporter and believe the primary is over, your job now is to make Sanders supporters feel welcome in the Biden campaign. There's *no* argument for either Biden or his supporters saying the primary should be shut down for anything but public health reasons.
PS4/ To be clear, like everyone else I'm not seeing a path for Sanders at the moment apart from a huge (historic) victory by him at the upcoming debate. But as an attorney who believes in *rules people agreed to beforehand*, I'd say what I'm saying now no matter *who* was ahead.
