Bono, Edge, and Larry are all big time Christians, while Adam is the only "wild child" in the band.
The three believers spent their first US tour sitting in the back of the tour bus reading their Bibles, while Adam wanted to go out to nightclubs and party. It nearly split up the band, and furthermore, Bono, Edge, and Larry actually had conversations during the 80s over whether or not being in a rock band was in line with their Christian principles.
I for one am happy that they used their fame to bring a spiritual message to people through their music to people who would have otherwise not heard that message (especially in the 80s with albums like The Unforgettable Fire, The Joshua Tree, and War).
I also don't agree with Bono on everything but he makes his faith very clear here and it is a message that all Christians can agree on. I also admire his work in getting debt reduced around the globe, his plans could use a little work, but otherwise, a noble cause.
You sound like a bigger U2 fan than me!
I didn't relalize that moral/religious differences almost broke up the band. I still love them and would be disappointed to see them go, although I didn't think Vertigo was their best work. I think the Joshua Tree is the best album, ever (see my profile ;-) but War has a special place in my heart, as listening to that album is how I became a fan.
I, too, don't agree with Bono on everything, but he is genuine, and as you correctly point out, unlike other celebrities, he gets educated on the issues he cares about!