But in some sense you do, because you don't come to a dead stop at every intersection, even when it's green. And it's a bitter pill to swallow, but no amount of defensive driving can make you totally safe. Getting rear-ended sucks.
Sure, but you can take some relatively easy actions to significantly reduce your chance of injury by a crazy driver. I don't come to a stop at green lights, but I do glance both ways to see if there's oncoming traffic. Occasionally there is: I've seen people blatantly run red lights.