And yet some places (California for instance) are attempting to do just this by requiring some kind of vaporware AI mediator to review files before the machine operates. Intermediary liability is out of control.
It's not illegal to sell these because it would be illegal for the end user to make a gun with them (it might or might not be - but is irrelevant) - it's just illegal to sell them because the legislator said it is.
This same trend is happening all over, from banking to communications to manufacturing, where private industry is deputized by force to police consumer behavior, without consumers receiving any of the usual protections provided by the legal process. We’re effectively witnessing the construction of a privately mediated police state.