The other passage that tends to be referred to in this context is 2 Corinthians 3:15-16, which refers to people who have a veil over their hearts when “Moses” is read. There, if one reads the whole context, it becomes clear that what is being referred to is not a veil that prevents understanding, but a veil akin to the one placed over Moses’ face in Exodus 34, which hid from view the fact that his face shone and that the glory with which it shone faded over time. And so Paul expressly says that the veil prevents some from recognizing that the glory of the old covenant, like the glory of Moses’ face, is one that fades.
Atomistic interpretation also is a factor. Quoting just a verse from 1 Corinthians and a couple of verses from 2 Corinthians, one can easily persuade oneself that the meaning is what fundamentalists claim. And so by treating the Bible as a collection of verses to be used independently of their context in the Bible, fundamentalists mistreat and disrespect the Bible and thus misunderstand it.
But perhaps most ironic is the fact that the context of the passage in 2 Corinthians is a contrast between the letter that kills and the Spirit that gives life. Focus on the letter – not only the written letter per se, but in particular the letter in abstraction from the other letters around it, and the word or verse similarly isolated – is characteristic of most forms of Christian fundamentalism. And so while thinking themselves wise interpreters of the Scriptures, they fundamentally misunderstand them. And while accusing those with whom they disagree of not having the Spirit and thus not understanding the Bible, they focus on the letter and themselves miss Paul’s discussion of the letter that kills and the Spirit that gives life.