I'd strike the words "carry a firearm when they". Some individuals will pose a danger to the public if they not kept under very close supervision (as in a prison), whether or not they are legally allowed to acquire firearms. Other individuals will not pose a danger to the public, whether or not they are legally allowed to acquire firearms. While there are a significant number of people who don't pose much a danger to the public without firearms, but would pose a danger if they had them, the vast majority of those people, while legally allowed to buy a gun, are disinclined to do so; there is thus no need to restrict them.
Thus, even if rules restricting firearm ownership by convicted felons would be constitutionally justifiable, it's unclear that any legitimate good they accomplish would outweigh the illegitimate harm caused when they facilitate the denial of the rights of people who are not accused of having done anything illegal, nor of being incompetent to handle their own affairs.
So...you’re in the ‘let a felon buy a gun regardless’ category? That’s your right, and if the people in your state agree with you then I don’t have a problem allowing you to set your laws whatever way you choose. But if the people in my state decide that they don’t want to trust those who had been convicted of violent crimes to own a gun when they get out, or allow a person diagnosed with mental issues to own a gun, or allow a 5 year old to buy a gun even if his guardian says it’s OK, then I believe we should have the right to do so. And I don’t want the federal government to say that some other state can override our laws.