They may have a mechanism in place, but your argument falls flat at complaining about this mechanism (or any undemocratic mechanism) when it hasn't even been used to change the final results of any election.
I guess you could say that Democratic voters are a lot better at nominating the person their party leadership wants them to than the Republican voters.
Who's talking about Hillary ? I'm just saying they have a mechanism in place to make sure there is no actual democracy going on. I didn't claim they had to use that mechanism in this election.