Your analogy bears no resemblance to the matter at hand. The victim in this case was laying prone on the ground with his hands behind his back and was shot in the back. In your analogy, you'd have to drive off the road and run over someone laying face down in the ditch and kill them, and yes you would be guilty. And intent is not always the reason why the guilty are guilty, it's called negligence.
Yep. When you don't look at facts and intent, then it does boil down to someone "lying prone on the ground and getting shot in the back." Juries have to look at more than superficial circumstances.