Again, your line of reasoning ignores the “trained” aspect of a Militia, and implies that everyone who isn’t subject to conscription isn’t People.
If you want to suggest that the state-based National Guard should train all adults in “military exercise”, including the responsible operation of firearms, you’ll hear nothing but support from me. I believe that everyone, leading into adulthood, should receive training roughly in line with the concept of JROTC. I believe this, or comparable training, should engage nicely with the 2nd Amendment.
I do not believe that every unhinged yahoo having access to firearms is desirable. Driver’s Ed is actually a great parallel. If you cannot demonstrate that you are capable of responsibly operating a vehicle, you are not permitted to do so, at least not in public spaces. If you cannot demonstrate that you are capable of responsibly wielding a firearm, you should not be permitted to do so, at least not in public spaces.
If your objection, as tends to be the case, is “Then the government will feel too comfortable limiting the check popular firearm ownership places on despotism!”, this isn’t the 18th century. The standing Army can easily overwhelm any grassroots opposition.
If your objection is something else not addressed, I will be happy to respectfully consider and engage with it.