we do have some military style groups- but not many- but really- the constitution is not just about allowing arms for militia, it’s also about allowing them for all citizens and not infringing on that right- that inalienable right.The Supreme court made it clear that the right extends to all citizens, whether they belong to an organized group or not
But don’t forget also- We farmers and ordinary citizens are who drove the British from our shores- many folks not belonging to actual proper militia groups defended this country against a foreign enemy
Those volunteers were called “Irregulars”. In reality, they and militias were almost useless to Washington’s plans since they would fire a shot and run. That tendency was later successfully incorporated in the tactics of the Continental Army.
At the time of writing it was not thought necessary to define “militia” it was understood as the armed force of the able-bodied within a community.