Killing a CEO is still doing nothing about the deaths caused by the insurance industry. How would it save lives of people harmed by privatized healthcare? If anything, it makes that anti-private-healthcare crowd look like a bunch of murderous zealots and will drive away any sympathy, making the problem worse. See: effect on indian raids on views of Native American rights, effect of Hamas attacks on views regarding Palestine, etc.
This is more like you let the train go and kill 5 people, or you pull the lever and kill one person, but that track loops back around onto the same track and kills the 5 people anyway, and then keeps going and kills 5 more people just tied on the part of the track the train already passed.
Let's be real, many would pull the lever anyway because they just want to feel like they did something about it.