That's a mis-understanding of militia. In the age in which our Constitution was written, militia was understood to be any and all males of adult age. If you were an able bodied adult, you were in the militia. There was a general understanding that you were supposed to be ready and able to help defend yourself, your town, your friends family and neighbors.
Now we have babies posing as adults who are not willing do defend even themselves, let alone anyone else. Nor have the means or ability to do so if they wanted. This has given rise to the criminal underlining of our nation that fears nothing, because it doesn't have to.
If you want a great example of militia, look at Switzerland. Everyone is required to be in the militia. They have one of the highest gun ownership rates in the world today. As part of militia service, guns are stored at home. Nearly every household has a military grade weapon at home.
Yet, the Swiss crime rate statistics say.... huh? What swiss crime rate! The people of switzerland do not even record the crime rate because it's too low to bother with!
When you think about it, it make perfect sense. Would you try and break and enter in someone's house knowing every single person along that street, including the target home, has a military rifle that could be used in seconds to shoot you? Would you mug someone knowing every person on the street or in nearby buildings, all have military grade weapons at their disposal? OF COURSE NOT!
This is what the founding fathers envisioned with the right to keep and bare arms. It works for the Swiss, it can easily work here.