The militia act seems more about being able-bodied and of proper age. It doesn't have to necessarily do with owning a firearm
I wouldn't object to being "registered" as a gun owner if I could be certain that the purpose was so the civil authority would know where to reach me if they needed to call out the militia. However, since any registration today is VERY much more likely to be a prelude to confiscation, I oppose registration.
While I 100% agree with you, I believe modern politics shows us that all laws with "good intentions" will be abused