"Why do you need to own a weapon like that?" - Piers
Answer: why do I 'need' to play video games? Why do I need to watch TV? Why do I need to buy the cereal with the blue packaging rather than the one with the red packaging?
It's none of your d@mn business why I 'need' to own something when the fact is that gun ownership is a right provided by the Constitution of the United States!