Ever run into a POed feral hog when out hunting? If so, you'd have all the reason you'd need to have one. Staring down a charging feral hog knowing you've got 4 s s in the tube to deal with it sucks.
And frankly, sometimes it's just fun to go shoot one. Sorry that's lost on you, but some people want to watch TV, some play video games, some drink, some smoke, some of us have fun going out and hanging up targets and taking a little target practice...
The funny thing is you and others apparently can't distinguish between the semi-auto lookalikes that are being villainized and the military grade auto weapons that are being used in the majority of the violent acts in Mexico.
You pull the trigger on one of these 'evil' assault weapons, you get one 'bang'. That's it. You have to pull the trigger each time to you want to discharge a round. But they look evil, and getting them banned sets the precedent among the anit-gunners that can be used to further ban additional guns through the court system. The Brady group has laid it out clearly, and has a close ally in Obama and another in his AG.
Ban these evil looking ones, then they can go after all semi-auto weapons (including hand guns) because they have the same rate of fire as the 'banned' assault weapons, and the courts have already ruled those illegal.
The progression continues until all firearms are banned.
But as others have already noted, the second amendment wasn't authored so I could go out and take down a feral hog, or defend my home in the case of a home invasion or buglary attempt.
It was enumerated so the people in this country have a check on out of control federal government, which is becoming more and more of a reality every day.