Same reason anybody else does. It's an implement of war. The 2nd amendment has nothing to do with hunting or even home defense as we think of it. It has to do with being able to organize a militia and go to war with anyone threatening the freedom of the people.
yeah, i can understand that point of view but i see such weapon as having one purpose in the hands of an individual and that is to kill lots of americans very quickly. i wouldn't mind them being regulated such that they are kept locked away and well recorded at ranges and militia armories, though i cant imagine any militia would want to keep their weapons in one place that the feds know about, but still, machine guns in the hands of civilians will lead to machine guns in the hands of stupid or mentally unstable people.
one purpose in the hands of an individual and that is to kill lots of americans very quickly
That's not what that gun was made for. It's for controlled fire on specific armored targets. It's also stationary, you can't just walk around with it.
Here's my opinion, for what it's worth. Anybody can kill civilians through an incalculable number of ways. We have cars and other heavy machinery, we have fire, we have chemicals (and by extension explosives), etc etc. A machine gun, or any gun, is certainly another way. We can't stop the next mentally unstable person going on a rampage by the means you suggest. That's the sad truth of it. A .50 cal machine gun is specifically made for armored targets, and civilians are not armored. You could argue that it also allows pulling up to a building and shooting through the walls, but that's entirely unnecessary to kill civilians and also not very efficient.
So if we can't effectively limit the means available to the mentally unstable person, that leaves us with treating the mentally unstable person himself and the conditions that surround him. We could do this though health care programs specifically designed to help those people, dumping testosterone inhibitors in the food and water supply (though a fucked up chemical imbalance could exacerbate the problem), more comprehensive pattern analysis, economic improvement (people only do crazy things when they're at their wits end), and more ready available stress relief (like being able to fire a .50 cal machine gun). Never have I been to the gun range and felt bad or depressed afterward.
Ultimately, gun control is only effective at protecting government from their most compliant of citizens, and I believe it's only through propaganda that anyone believes this is a good thing.
stupid people are why gun control should be tighter imo. i'm not saying guns should be banned but why in gods name does an individual need a .50cal machine gun?