The founders were horrified of standing, full-time armies. Thus, Amendment Two was drafted. But that aversion to full-time standing armies died out a long time ago. The federal government has theirs and the States (with their National Guards) have theirs. Both are armed by the citizens through taxation. Such being the case, we no longer need the citizens to arm nor serve in the militias when they are constituted and called to duty for the States. Hence, we no longer need the Second Amendment.
If you're a Constitutional "originalist", I can't see how you fault that reasoning.
If you're a Constitutional "originalist", I can't see how you fault that reasoning.