Look, I said it may sound ignorant but, that doesnt mean that it is. A weapon is a weapon. A more "advanced" weapon will kill just as well as any other weapon. I think that most gun crimes that I have heard of were performed with pistols more often than any other type of gun I can think of.
Now here's the solution that you are asking for, do not ban any weapons. Allow people to own whatever they want. Wow, that was easy. Now here is where the real problem is, how can regular people like us ever stop this from happening? We cant, the politicians will vote however they think will make them look better. You can try to contact your local representatives but, you know as well as I do that nothing will come from it. So new plan, buy all the guns you have ever wanted while you still can.
And the there is no better explanation for why people would "need" assault weapons than because they WANT to. Whats so hard to understand about that. I dont understand why thats not a good valid explanation for the situation. And if shit ever hits the fan and we do have to defend ourselves from the government, everybody in this thread will rise to the occasion and will be prepared to do so except for you and that fiji fella.