nailed it earlier. The full text of the relevant law is here
, but the important parts are that for the training to be unlawful, the person conducting it must fall under the "knowing or having reason to know or intending that the same will be unlawfully employed for use in, or in furtherance of, a civil disorder within the United States
" wording of the law.
Also, further down in the law, it explicitly says that "training or teaching of the use of weapons to be used for hunting, recreation, competition, self-defense or the protection of one’s person or property, or other lawful use
" is strictly NOT prohibited by the law.