First, I don't subscribe to the idea that people only have those rights listed in the Bill of Rights. But that's another thread.
And once again, the 2d Amendment is not absolute. Even the 1st Amendment, which uses absolute phrasing, has been interpreted to have exceptions.
Do you agree that there are valid exceptions, such as bans on automatic weapons, cannons, grenades, missles, sawed-off shotguns and bazookas? If the purpose is to protect my ability to join a militia, why can't I purchase my own Apache helicopter? And if the 2d Amendment does not invalidate those restrictions, why should it invalidate rules that ensure people who own guns are properly trained in their use?