Two things:
1) Static Impulse was recorded in Sweden while DT was on tour. It was written before that.
2) We don't have any means to confirm what SystematicThought just said is true, just some words from someone we don't know of something MP supposedly said while he was upset about the whole thing, and, even then, I remember clearly the words were "never seen a person less involved". And from Mike's point of view, sharing writing credits, sharing spotlight with another singer (in JLB's case screamer) and not being there to oversee the recording constitutes lesser involvement just fine. Is this not a reasonable explanation?
I honestly don't know why is it so shocking to people that James writes music.