"Why do you need an AR15?"

[stanc]

Let's reset this discussion and go back to the original post.
I learned some interesting things from the previous discussion, but let's let that rest, and try a different tack.
After every mass shooting, would-be gun banners demand: "Why do you need an AR15?"
I think it would be useful for us AR15 owners to have a short answer ready. An answer that is reasonable, respectable, that hopes to win the uncommitted over to our way of thinking.
Pretend, for the sake of argument, that the questioner is actually sincere, and merits a sincere, respectful answer in return. What would you answer, in as few words as possible?

I think it's a very bad idea to validate the question by giving any reason to "need" an AR15, because it may help open the door to legislation requiring gun buyers to demonstrate a need acceptable to the government. As an example, look at the situation in many parts of California, where one must prove a valid need in order to obtain a CCW permit.

My proposed response: "This is America, not the Soviet Union. People are not required to justify buying an AR15 on the basis of need."