Um, I am going to assume you haven't seen clips of their set or haven't heard about it. I don't want to spoil it for you but it was one of the biggest let downs in the festival's history.
I disagree. I thoroughly enjoyed it despite some of the awkwardness. I definitely wouldn't call it one of the biggest let downs Coachella has ever seen, but to each their own I guess.
To be fair, it seems like this is primarily an American problem. I can't say that I've ever seen a video from a European festival without a pretty top notch crowd. Not sure why we have such a problem here.