Unfortunately you can't expect primary voters to actually bother figuring out who their candidates are. For some reason Tennessee seems to have a worse problem than the nation as a whole with this. But it's bad everywhere. Other than the Atlas types no one has a clue who their primary/lower level office candidates are.
This is not an Alvin Greene situation. He's the incumbent.
I am aware. I just don't think most of the people of his district actually realized all the stuff he's done when they voted for him.