"Vicarious"
In an interview, Hideaki Anno (writer & director of Neon Genesis: Evangelion) was asked what he thought of the immense popularity of Evangelion. He replied that it was one of the saddest things he could imagine. That so many people could relate so strongly to a story about this sort of pain was depressing beyond belief. (Note that I don’t have a primary source, only a recollection of an anecdote someone relayed. Please take this as apocryphal at best.)
So in one sense, I think it’s a good thing that everyone seems to be trying so desperately to “find the motive” of the Germanwings co-pilot. It means that most people do not intuitively understand that mindset. It means most people have not felt that particular despair. This can only be a good thing.
But honestly, I kinda wish they would stop. I think that this is one of those things you either get immediately, or you never understand at all, and no amount of digging and prying can truly make you understand. And that is for the best. Let it lie, and just accept that he was a sick mother-fucker, and sometimes true evil does exist. Criminal investigation should continue, to ensure there wasn’t any other party encouraging him that should be hunted down and punished for their part in it, however unlikely that is. But this pop-search for “what drove him” won’t lead to a deeper understanding for any casual observer. At this point it’s little more than entertainment, and it’s distasteful.