They also said that the 2nd amendment guaranteed the right of private citizen's to own and carry firearms. That good enough for you that you will demand that your politicians stop trying to pass laws contrary to that opinion?
First, it is arms, not firearms. It does not specify or limit types of arms. However, the constitution does specify a framework for laws and judicial review. Therefore it is reasonable to allow laws to specify or limit types of arms (unless you think your next door neighbor has a right to have nuclear bombs).