Read it again. It says that if the legislation stopped at forbidding concealed carry only, it would have been "legal". But that since it forbid all carry, that it was against the Constitutions Second Amendment protections and void.
So Congress may impose a national concerned carry ban pursuant to the 2nd Amendment, by your "logic". No wonder you and Sarah hate state laws so much. They stand in the way of your dream of centralized power imposed by judicial fiat.