The argument that superdelegates hurt Hillary's campaign is equivalent to the argument that Cruz's victory in Colorado helped Trump. Victories always help you, that's the point of them. You can fight your opponent painting your victories as unfair, but your opponent can't really fight the edge in delegates you gained by your victory.
The difference is that "momentum"/bandwagoning actually existed on the GOP side. After NY the party's voters collectively decided enough is enough and wanted to get the primary over with. That may have partially been due to Trump's rigged system arguments.