Depends which country you are from. The motivation to own a gun in the UK is for sport, vermin, farm use, river wardens etc.. In Switzerland, their culture is to own a gun to protect their country from outside aggressors.
And if you're from America, like you and countless gun nuts here, you all claim it's to shoot your fellow countrymen for self defence.
No one has to ask why you own a gun because you guys have stated here why, self defence, to shoot others. What a stupid thread, but there again, you are a gun nut.