I don't think that's exactly correct. Sometimes it is, no doubt, but there are a lot of scenarios where the bad guy gets close and you couldn't avoid it. Also, the moral dilemma a person has to go through before shooting someone --- no.. nevermind, in that case they're probably an idiot. We should be practicing not just the physical part of our self-defense but also the moral, ethical, and emotional questions. Those all need to be so fully rehearsed and practiced that we're able to work through them in the split second we may have in a situation where we're attacked or threatened with attack - so ignore my though about the moral part but, still, there are scenarios where someone might get close and you couldn't prevent it.