Because one is protected from government in the Constitution. It literally says that the government cannot infringe on one's right to keep and bear arms. It doe

Because one is protected from government in the Constitution. It literally says that the government cannot infringe on one's right to keep and bear arms. It doesn't say the government allows you to have them. It says the government cannot disallow you from having them.* *Note: the government could disallow one from having them so long as that person goes through due process, at which point Constitutional restrictions placed upon the government are relaxed in specific areas.