People voting for the only candidate they want just doesn’t strike me as a failure. The failure comes when someone has to vote for someone who is not their pref

People voting for the only candidate they want just doesn’t strike me as a failure. The failure comes when someone has to vote for someone who is not their preferred. That said, the 2016 Dem primary doesn’t seem like a useful example for testing the constraints of any voting system since there were really only two viable candidates. All methods work equally well under those conditions. Why would someone approve both of the only two candidates when only one of them could win?