I simply refuse to see how it was a bad decision to support Halter. Lincoln is just a horrible candidate who is most likely going to lose in November anyway, was notoriously and openly hostile to just about everything important to the Democratic base, and the netroots were able to find a good solid candidate to attempt to primary her. If ever there was a case to primary someone, this was it- there was quite literally nothing to lose and everything to gain.
And Halter came very, very close to beating her. I just fail to see why anyone should be embarrassed, or feel foolish or demoralized. Sometimes you win, sometimes you lose, but you always lose if you never try. Rather than mocking the attempt or getting some schadenfreude because people you don’t like on the internet feel bad today, you should get off your ass and make sure this sort of action, primarying bad politicians, becomes more rather than less common.