Because the militia is necessarily made of the people. There are even definitions for the implicit militia in 10 US ss 246. When individuals were conscripted to

Because the militia is necessarily made of the people. There are even definitions for the implicit militia in 10 US ss 246. When individuals were conscripted to fight in the militia to put down the whisky rebellion, they brought their own arms. There is an interesting history of how those arms were treated - even exclusions when property was seized by the courts to pay debts the militia related arms were not taken. By leaving the arms with the people rather than only issuing them when their is an uprising lends itself to the "well regulated" part, as regulated has a different meaning when used to describe soldiers/units of the period - generally skilled and disciplined, which requires practice. There really is a lot to read into and interpret in many areas of the constitution based on the language differences from then vs now, the the second amendment being a prime example.