If you read these bills, you'll find that Congress claims the authority to pass such legislation under the New Deal "substantial effects" doctrine.
"I write separately only to express my view that the very notion of a ‘substantial effects’ test under the Commerce Clause is inconsistent with the original understanding of Congress’ powers and with this Court’s early Commerce Clause cases. By continuing to apply this rootless and malleable standard, however circumscribed, the Court has encouraged the Federal Government to persist in its view that the Commerce Clause has virtually no limits. Until this Court replaces its existing Commerce Clause jurisprudence with a standard more consistent with the original understanding, we will continue to see Congress appropriating state police powers under the guise of regulating commerce."
-Justice Clarence Thomas
It seems everyting would fall under the commerce clause. Starting with the Post Office and “ending” with the Internet.