OK, so I'm going to have to generalize a bit, too many posts to quote.
@pastera seems to be saying, and correct me if I'm wrong, that suppressors are under 2a because past legislation and case law says so. Well I started with the pretense that this was the problem. That it is a "just because" loop without any logical step by step process that makes them an arm (covered under 2a).
As for them not being an arm but covered under 2a, whatever, I'm pretty much using them interchangeably. If it makes a difference to you, my use of arm means covered under 2a, and my use of 2a means an arm.
For those that say the gov can regulate anything. Not entirely correct. Without a law allowing them to regulate something NO they can not. The ATF cannot just start regulating trucks because they don't like them. And if they claim they are a weapon (an arm) then they would fall under 2a and that would limit what they can do.
The gov certainly can try to pass a new laws giving them the ability to regulate anything. And they do it all the time. But there always has to be at least a pretense as to why. Chemnicals and other things that are not arms/weapons are usually argued to be dangerous, and this would not make them covered under 2a. But if suppressors were not arms, what would the gov claim is the reason to regulate them? If they say they enhance the use of a firearm, BINGO they now fall under 2a. They need to find a reason that has nothing to do with their use on a gun.
So tell me, what is the reason the gov NEEDS to regulate suppressors that is NOT because they enhance the use of a firearm. And that NFA says so is not proof, it was passed on the idea that gangsters or assassins would use them to make guns silent, at a time when real data was both more difficult to get and the myth was hard to disprove. Today we have piles of verifiable data that says they are not used in crimes to any significant degree, and the affect they have can be clearly demonstrated.
As for those that say the law is what it is so none of this matters. Well of courser the law is what it is, I'm not saying otherwise. The whole point of this is the laws are wrong. Not the interpretation or enforcement of the laws, but the laws themselves. And I'm asking for a logical reason why they are right/ Something that stands on it's own and doesn't rely om some other opinion or unsupported law.