A presumption of ignorance is totally fine with me, and not in opposition to a presumption of innocence, IMO.

I don't see any restriction of rights in the need for a driver's license. Auto accidents kill a lot of people, too.

I appreciate that we can all sign away our rights to join military, and that so-doing conveys certain subjective benefits, but that's really not an argument that's respectful of an assertion that all people deserve equal rights under the law.

To the final point, I am opposed to Congress getting to say that the groups of citizens which they directly control (the military) can have all the guns, but the group of citizens that they do not control cannot have all the guns.