This is America. I don't need a reason. It's guaranteed by the Constitution, but if you really want a personal answer, it's because as a retired LE officer, I saw a lot. Regardless of what some might think, we actually did take an oath to protect the public, and firearms were meant for more than just protecting our own lives. A lot of men and women wearing badges have put themselves in harm's way to protect citizens. Many have paid the ultimate price.