meh. the article makes it very clear what she was convicted of:
Rosenberg was tried and convicted on the following charges: “Conspiracy to possess unregistered firearms, receive firearms and explosives shipped in interstate commerce while a fugitive, and unlawfully use false identification documents …; possession of unregistered destructive devices, possession of unregistered firearm (two counts) …; carrying explosives during commission of a felony … ; possession with intent to unlawfully use false identification documents…; false representation of Social Security number, possession of counterfeit Social Security cards.”
I suspect snopes is concerned with a libel charge. Susan is not a convicted terrorist. She is a convicted $ALLTHETHINGS. Sure, it sounds a lot like terrorism, but that isn't how the courts work.
I have no idea where Susan or Snopes are located, so can't comment on the libel law in the states in question.
IANYL.