The simple answer to that is "other Democrats", if we're honest. Necessary reminder that the best thing you can say about Democrats is at least they're not Republicans.
Especially when they blame it on Clinton, as if she was a "bad candidate". Yeah, that doesn't erase the ~63 million Americans who looked at Trump and said "oh, fuck yeah, that guy!"it's almost like 2016 is just an easy excuse for certain people to lazily pin the blame for their chosen political parties abject failures on.