Oh look at all the oh so hip hipsters trying to outdo each other by saying how much they hate a band that they're supposed to hate. "I hate them so much I've never even heard of them!". Whatever. They may not have the best catalog and are not as relevant as they once were... but they were (and are) one of the biggest bands of all time. And although I'm not a huge fan myself, Joshua Tree was and is an absolute masterpiece and always will be. That album be remembered LONG after whatever other crap you and I are listening to today is long dead and forgotten.
True, U2 hasn't been relevant since Joshua Tree (it is a good album BTW). But U2 is basically just another Aerosmith these days, playing to mainly the Baby Boomers, Teeny Boppers, and people who are generally clueless pop fans.
I'm kind of embarrassed that they're rumored to be performing at an Apple keynote event.