Why do people argue that they need ARs and shotguns and such?

There is much debate over the subject but I just understand the need of an ak-47 or assault rifles or sniper rifles and huge *** shotguns. These guns are just not practical in the way of self defense, any handgun is enough to take someone down. An assault rifle and sniper rifles were developed specifically for combat, not civilian use. Y can't people just use the ones at the range if u want to do it for target shooting. Others suggest removing guns completely but that don't stop criminals from getting them in fact it's better cuz now there ain't sh*t to protect urself. Even if guns are out of the picture there r knives, bats, fists. Human nature kills, a gun is simply a tool. Anyway then people want silencers and when the gov. Says f*ck no, they ***** but u hav to c that it is the perfect murder weapon. Why r ten 9 mm - .50 AE not enough? Or even just a regular semi auto rifle u know 5 rounds .22 cal or something like that. As far as "the right to raise a militia" I do not c any foreign armies coming to the homeland anytime soon. If u want to use an AR or LMG or sniper rifle, just go to the range or join the army. What is ur opinion on the matter? Maybe I missing something, though I doubt it.