your premise assumes that the ONLY regulation possible is a government organized and controlled entity. So lets take a look at what 'regulate' is defined as.......
verb (used with object), reg·u·lat·ed, reg·u·lat·ing.
to control or direct by a rule, principle, method, etc.: to regulate household expenses.
to adjust to some standard or requirement, as amount, degree, etc.: to regulate the temperature.
to adjust so as to ensure accuracy of operation: to regulate a watch.
to put in good order
given these definitions, and the multitude of historical references by framers and commentators before, during, and after ratification...............what do YOU think 'regulated' referred to when they considered the militia as a body of the citizenry???