I have no idea why you think the Dems are confident about winning. This is still Georgia, land of Lester Maddox. The Republicans have already gotten Senators reelected that the Dems thought they would beat, in Maine and NC.

These Republican Senators represent all of the big flaws of the Republican Party. They are greedy, uncaring about the poor and middle class, and still hold some of the old Georgia views on race. But that doesn't mean they won't win. It probably means they will.