I think the problem we are running into is the difference between someone who is and has been in your home and refuses to leave VS a person who breaks into your home and refuses to leave. Obviously the person in scenario 2 is up to no good, and most likely shooting him, even in California would not result in your prosecution. Scenario number 1, is different, and you can't shoot someone who is just loitering in your house, but you can have them removed. Obviously if you are the victim of a home invasion, that is different. But, doesn't that go without saying?