From what I remember, most data we have on people with a severed corpus callosum comes from maybe a handful of instances, far too few to extrapolate any reliable information from. I'm also going to point out that this thing sparked the whole "right/left brained" bullshit that's been passed around by the ignorant for most of my lifespan, so I'd take ANYTHING related to it with enough salt to preserve a small whale carcass. And the general Christian viewpoint on sin is that it has to be: A: Made with full knowledge of the consequences and B: Made with full control of your faculties. Someone who kills someone while drunk is guilty of a lesser sin then one who performs the same act in cold blood. Having a dual identity due to having your brain fucked with[Not even sure that's possible outside of fiction, I have little to no knowledge on the subject] would inhibit B and possibly A, making any sinful acts committed by said person not their fault. And I'm also fairly sure disassociative personality disorder doesn't actually make two different people, merely one very very confused person who BELIEVES they are different people.
EDIT: ^In case you haven't noticed, please take anything I said about psychology with a standard civilian issue salt shaker. I am far from an expert on the subject. Also, people post really fast. Its almost like they've all been trained in ninjistu while my back was turned.