Well, Im not sure about who wrote really Creed songs, but is clear that (even though Creed in my opinion was not a Christian band) Stapp gave to the band a Christian outline even though after he denied it a lot of times. He clearly showed it in the lyrics using a large number of religious references, what was not a bad thing, Faceless man, for instance, is definitely a great song and its full of religion references.So we dont have a problem here.
I can't understand why some people here are finding difficult to notice that.
As for U2 (which is my first favorite band
) in my opinion they are not a Christian band either and they never were, even though Bono wrote a ton of lyrics refering to the spiritual things.