I had a good time in Vegas, so I didn't spend a huge amount of time at NN, but I did spend enough time to take in the mood, and it was schizophrenic. About half the people there are some combination of angry, disappointed and bitter with Democrats in general and Obama in particular.
This group sees him as not a heck of a lot better than George Bush, and in fact the Democrat who extended some of Bush's worst policies, especially in civil liberties. This includes a lot of feminists (angry at what they see as betrayals on abortion), many Hispanics angry at the continued harsh enforcement of immigration laws, gays who feel Obama has betrayed clear promises on gay rights, anti-war activists saddened by escalation in Afghanistan and elsewhere, and a mishmash of folks who think health care reform was a dog's breakfast and that the general way the economy and financial reform has been handled is a disgrace.
Then there are the folks who would characterize themselves, in general, as hard-nosed pragmatists and "realists". These range from the "Obama is the greatest liberal president since FDR" types, who think that the Obama is just wonderful and those progressives and liberals who don't agree are simply delusional to those who feel that a lot of what he's done has been watered down pap in general but that it's certainly better than nothing and that those who are disappointed are unrealistic idealists who simply don't understand the constraints Obama and Congressional Democrats are working under.
As regular readers know, I tend to the first camp, but I'm not going to go into why, I simply want to note that this divide is very real. It's occasioning a lot of anger on both sides. The first sees the second as tribalistic sellouts, willing to excuse horrible things they would never excuse in Republicans so long as they are committed by Democrats and lacking an understanding of just how bad Democratic policy has been. These are folks who tend to sneer at the "wins" as either illusory or so underwhelming as to be a parody of the "lesser evil" argument. (Reminding one inevitably of the T-shirts which say "Why Vote for the lesser evil. Cthulhu 2008.") To many of these folks the other side are, crudely put, sell-outs.
The second side is angry at what they see as fairy-tale thinking and deeply unrealistic. "Obama couldn't fix everything immediately, but he's better than the Republicans will be if they get back in power" is their mantra, ranging from "really, he's wonderful and you're insane for thinking otherwise" to "well, yes he sucks but he sucks less than what the Republicans will do when they get in power." Either way, they see the attacks from what they consider the "purists" as deeply damaging. Democrats may or may not be a ton better than Republicans, but either way, they are better, and there is a moral case to be made for sucking it up one more time and working hard to elect, as the old progressive battle cry runs, "better Democrats". This is a two-party state, with those parties having an unbreakable oligopoly on power. Dissing Democrats just helps the even worse party win, at which point they will do even worse things. So get over your problems, whether they are with economic policy or Obama's continued shredding of fundamental civil liberties like Habeas Corpus, jump back into the trenches with your bowie knife or bayonet and fight for Democrats, not against them because by constantly bad mouthing Dems all you do is make it more likely that Republicans will win, and if they win, well, that will be baaaaddddd. Very, very baaaaaddddd.
To put it crudely and unfairly to both sides, it's the sell-outs without principles against the purists without realism.