Secret holds are just one of many insane Senate traditions that can be used to impede progress. In an effort to preserve them, DeMint used another. He attached a "secondary amendment" to the Wyden/Grassley amendment. Now, if you voted for the amendment to end secret holds, you'd also be voting for an amendment establishing a border fence.
World's worst deliberative body. Also, click the link above the quote, Ron Wyden's rant after Demint sank his amendment is very entertaining.