Plenty of Democrats stayed in the chamber to watch the speech in person. They weren't the hypocrites who left the chamber like petulant little kids and then watched the speech on their office TVs. Some who stayed liked it, some didn't. Virtually all in the GOP agreed with the speech. But many of the Democrats were offended and upset. The reason why is the very same reason virtually everyone in the GOP liked the speech: It was a historically accurate and logically cogent appraisal of the situation.
Democrats, often, hate reality. The live in a world they wish existed rather than the one which actually does exist. I call it delusion, but a more positive spin on it would be idealism (idealism is a great thing when checked by living within one's means, but that is another article), but whatever it is we end up one day at the same place, which is at the unintended and almost always negative consequences of their silly ideas. It's why in the case of Iran so many people are worried, because the silly idea of letting Iran keep more working centrifuges than needed for a "peaceful" program, and not destroying the remaining mothballed centrifuges (so they can be restarted with relative ease), and sun-setting the deal at ten years, and even of giving Iran a unilateral way out when ever it wants, leads the logically-thinking person to realize such a deal actually allows rather than prevents Iran from getting nuclear weapons.
War, as an unintended consequence, is far more likely with Mr. Obama's deal with Iran than without. Without it some covert action, or overt military strikes, to deny Iran nuclear weapons would be likely, but it wouldn't be war. With Mr. Obama's deal those strikes would be more difficult (not impossible) to conduct by third party nations, like Iran and KSA, and will give Iran even more time to protect its facilities and strengthen its national defenses. If strikes later would have a reduced chance of success, and are less likely sooner so long as a deal is struck, then later war is far more likely as a result.
In his idealistic (I would say delusional) mind I doubt Mr. Obama can see this possibility at all. To him he must think, as Mr. Netanyahu said, that Iranian mullahs will have some sort of awakening and will be changed by this deal. It's as if Mr. Obama truly thinks he has messianic power. Which is delusional.