In 1934 a bill was passed levying a tax of $200 (4 times the price of a Thompson submachine gun at the time.) on future sales of machine guns. Short-barreled rifles and shotguns, cane guns and silencers were also thrown into the bill, almost as an afterthought. The BATF was set up, and one of its functions today is to collect such a tax. So much of the controversy dealing with Title II weapons is not that they are illegal, but that a tax will be levied on their ownership. Owning one which is not properly registered and taxed is a violation of federal tax code (tax evasion) a felony punishable by large fines and up to ten years in prison.
Good Hunting... from Varmint Al
As I tried to point out earlier, and you apparently didn't get it, yes ATFE has a problem with silencers. No, its not legal to have one now without getting a "mother may I" from ATFE and paying your tax. That is a law that should be changed and this kind of thing (varmints) is the reason why. God Almighty didn't write "Thou shalt have no suppressors." Humans made the mistake of passing that law.
Not as an afterthought at all. All were demonized as "gangster weapons", (sort of like "Assault Weapons" or "Saturday Night Specials" or Cop Killer bullets). Heck the sponsers of the legislation tried to get ordinary *handguns* included. The NRA, in one of it's first legislative lobbying efforts, and its first compromises, short circuited that, in return for allowing the first unconstitutional infringement of the RKBA at the federal level to pass without it's objection.