They are not yet clear on why that particular one, or even whether it is their call.
As I wrote this entry, one of them said, "What's the matter, James? Don't you like people telling you you're going to prison for being a pedophile?"
I'll have an answer for it just as soon as people (and not demons) tell me that.
Update on June 20th, 2012: It is now assumed that Soledad was picked because it is the closest prison to the Bay Area. The Voices Demons are known to have a limited range; so, if I were shipped very far away, they would not be able to follow. Soledad, then, would appear to be within their range.