I actually did link the full text, but something in the post got mangled - not sure if it was me or Slashdot, but the link turned into plain text.
The key phrase in here is "including the federal obscenity laws." America actually has a federal law prohibiting-ish* all 'obscene' material on the internet, it's just that this law is seldom enforced because any effort to do so would be futile. It's a recurring complaint of the group Enough is Enough that this and some other laws are not enforced. The pledge is a masterpiece of political misdirection: It goes on a great length about child pornography, trafficking and abuse, but tucked away in the middle of it is a call to start cracking down on plain adult pornography as well. Of course no-one will publicly refuse to take a pledge which is almost entirely concerned with protecting children.
*Due to a rather complex tangle of laws and precedents, and laws specifically written to work around court rulings, it's not clear exactly what is prohibited. The Child Protection and Obscenity Enforcement Act. It doesn't ban pornography directly - that would be unconstitutional - but instead imposes upon producers and distributors record-keeping requirements which are quite clearly intentionally impossible to comply with. If you want to host a porn site, you'd better have on file the name, address and verified identity of everyone who appears, including all those amateur video uploads, so you can prove they are all over eighteen.