That's not how they worked when he was the nominee either, so he knows the system and how it works. When has any of this ever been a secret to anyone willing to open their eyes?
The bosses control both political parties and if they don't want you to win, you aren't going to win. Having said that, this is hardly ever an issue because both parties usually have several running for the nomination of whom the bosses would accept, but this year is different. The Republican bosses don't want Trump and the Democratic bosses don't want Sanders, so they aren't going to be the nominees.
Yeah, it'd be romantic to think that it would be the choice of members of the party who the nominee will be, but the Democratic and Republican parties are private organizations, the bosses have a lot of money and power at stake, they've spend years and years getting to where they are, and they aren't going to give it up without a major fight. And they make all the rules and they'll change the rules if it doesn't suit them. This is no secret, It never has been. If you voted for the Democratic Party all your life, you supported this system whether you want to admit it or not.
Carter knows all this. The questions is how many of you just recently figured it out or paid enough attention to now understand? Because if you haven't and it's suddenly a surprise to you, you're the only one there is to blame for not knowing how the system has worked for a damn long time .