In their defense, from what I gather, the festival was running late (reportedly because Usher went over his allotted time) and their set time was cut in half. I assume they knew going on that it was going to be abridged, but maybe not how much.
Haha. Wow. I can't honestly say that I blame him, though. Seven songs is an incredibly short set. And Green Day songs are usually on the short side, so what, they got to play for 20 minutes tops? He definitely went a little overboard though, and his "I've been doing this since 1988!" shit was pretty dumb.
While understandably stupid situation, why they didn't do something like just not play their set makes me suspicious. His whole demeanor did seem pretty irrational, but just the way that went down made me feel like it was pretty fake.
They went there to play and had fans there to see them; they would be foolish (and a lot more diva-ish) to simply not play, in my opinion. Not to mention they were probably contractually obligated.