E.g. 18 U.S.C. §1462. Importation or transportation of obscene matters.
He says: "Consequently, Congress explicitly indicated its intent to leave in force all the pre-existing provisions of 18 U.S.C. §1462.
In other words, giving out abortion information over the Internet, as of 1996, is illegal. Wow!"
Except when the Communications Decency Act was challenged in 1996, the government didn't even attempt to defend the enforceability of 1462(c), which prohibited the exchange of "obscene" materials over the internet. While not deleted from the code, it effectively can't be enforced because the government acquiesced on its obvious unconstitutionality. And the other parts of the CDA that they did try to defend were struck down by the Supreme Court.
You have to remember that "the law" in the U.S. isn't just what's in the statutes, it's what's in the statues + court decisions. There's a lot of garbage in the U.S. Code that can't be enforced because of court decisions like that.