Most of the people who wanted to prolong her body's existence are the kind who believe in an immortal soul, right? Thus they believe Schiavo has one. If you believe the report (and I'm not convinced they will--for these people science is as mutable as faith) then Schiavo was unable to feed herself, was blind, and in the vegetative state her husband said she was in.
So where was her soul? Two options: one, since she was brain dead (because, boys and girls, that's what it means to be in a persitant vegetative state--everything but the brainstem is shut down), her soul had already departed her body and was in the afterlife. Thus, letting the body perish is no sin since the soul has already departed. The second option is that her soul was still with her body, but trapped in a body that was unable to think, sense, or feel anything. I'd call this "hell" or at least "limbo". Not allowing the soul to enter the afterlife seems a horrible thing to do in that case. In either case, terminating life support is the only reasonable option.
Do you think the people who wanted to keep her "alive" will think this one through?