Some could be. Much of it is the primary symptom of schiz, and schiz is usually from a deep-seated miscommunication within the brain wiring.
Could be. But if that was the case, wouldn't the "voices" be more disorganized and garbled? It seems very strange to me that schizophrenics report the voices as being uniformly and persistently malicious.
How many schizophrenics think that they're being followed around by a big bunny in comparison to the number that are urged by voices to harm themselves?