I think it is used sort of the same way that fundamentalist Christians take the Bible "literally", as in, there's just the literal meaning of the words, no deeper symbolic meaning, usage of literary themes, allusions, etc. Fundamentalism also has a similar aversion to nuance. If you conceive of much of the world as driven by tensions between two opposites, fundamentalism chops off one of the ends. So for example, you have a tension between a subjective meaning (symbols, themes, allusions, etc.) and the objective meaning ("literal" meaning). As the late Rabbi Sacks observed, often the subjective meaning of the text runs counter to the objective meaning, and that counter- tension results in much deeper meanings than either alone.

I think he is observing that we live in a fundamentalist age. By "fundamentalist" I mean "there's one right answer", that is, no nuance. Even on the political Left, where you normally find some nuance, you get a fundamentalism that requires interpreting everything through an oppressor/victim lens that assigns groups to one or the other. So Palestinians are "victim", despite the fact that the Muslim view of homosexuality would be categorized "oppressive". White people are "oppressor" because they enslaved people, despite the fact that young white men died by the hundreds of thousands in a war to end slavery, and that the British Empire ended slavery in the Ottoman Empire by refusing to trade with them if they continued slavery.