“In Cases v. United States, a three-judge panel, all Progressives appointed by President Franklin Delano Roosevelt (FDR)...”
It was the NRA and activist members, who got handguns removed from the act.
Licensing and registering all handguns was the major thrust of the NFA bill. Machine guns, silencers, and short barreled rifles and shotguns were just the consolation prizes left after the bill was gutted.