The problem with Bayh is illustrative of the fact that being moderate doesn't always imply he is being moderate for you the voter as opposed to him and his brand instead.
Let's be honest, very few people go around describing themselves as extremist.
Obviously, but the point is are you going to make a compromise that is a beneficial to a significant chunk of people, or obstruct something over a minor tax provision that most wouldn't care about at all to please a few donors and get a headline about Bayh standing up to tax hikes. It is a stunt right out of 1999. That is the difference between a moderate statesmen and an exercise in moderate political branding.