Roberts is getting beaten in Red State Kansas. He knows the whole truth. He is getting desparate and blowing off steam. GOPe will reign him in. All these politicians know VJ is running the country.
I read it a little differently. He's getting beaten by a fake independent because people in soundly conservative Kansas don't really trust him anymore and would rather back an unknown. I think Roberts is throwing red meat out there to try to get the base excited about him. Probably none of this will ever be said again after the election, win or lose.
The difference is whether he believes it or not. Your theory presumes he's telling the truth in a sort of frustrated outburst, mine is that he's saying what he think the base wants to hear, and he may or may not believe it but will certainly never do anything about it.