As outlined below, an organization is engaged in “civilian military activity” if they meet any of the following conditions. This definition would apply to any organization that is providing or receiving instructions in the use of firearms or other weapons. Based on the lack of ammunition and firearms in this country, it appears that the government may be correct.
18 USC § 2386 – Registration of certain organizations
(A) For the purposes of this section:
“Attorney General” means the Attorney General of the United States;
“Organization” means any group, club, league, society, committee, association, political party, or combination of individuals, whether incorporated or otherwise, but such term shall not include any corporation, association, community chest, fund, or foundation, organized and operated exclusively for religious, charitable, scientific, literary, or educational purposes;
“Political activity” means any activity the purpose or aim of which, or one of the purposes or aims of which, is the control by force or overthrow of the Government of the United States or a political subdivision thereof, or any State or political subdivision thereof;
An organization is engaged in “civilian military activity” if:
(1) it gives instruction to, or prescribes instruction for, its members in the use of firearms or other weapons or any substitute therefor, or military or naval science; or
(2) it receives from any other organization or from any individual instruction in military or naval science; or
(3) it engages in any military or naval maneuvers or activities; or
(4) it engages, either with or without arms, in drills or parades of a military or naval character; or
(5) it engages in any other form of organized activity which in the opinion of the Attorney General constitutes preparation for military action;
An organization is “subject to foreign control” if:
(a) it solicits or accepts financial contributions, loans, or support of any kind, directly or indirectly, from, or is affiliated directly or indirectly with, a foreign government or a political subdivision thereof, or an agent, agency, or instrumentality of a foreign government or political subdivision thereof, or a political party in a foreign country, or an international political organization; or
(b) its policies, or any of them, are determined by or at the suggestion of, or in collaboration with, a foreign government or political subdivision thereof, or an agent, agency, or instrumentality of a foreign government or a political subdivision thereof, or a political party in a foreign country, or an international political organization.
h/t Jason G