Historically this is likely what they meant. Put it into context. The entire bill of rights is a check on the federal government. It is trying to strip specific rights out of the hands of government and place them into the people, or states in some amendments. So why would they check the federal government by allowing people to be armed, to preserve their own rights, only to give the federal government the power to regulate that right? It’s a contradiction. Historically, that is exactly what was intended by the 2A, allowing citizens to take back power by force if necessary.