I interpreted his words in light of their literary genre, which is a blog post containing didactic material. ;)
He decried those who teach the bible LITERALLY instead of LITERARILY.
And he did so quite rightly, though the dichotomy between literally and literarily is not so sharp as you are representing it as.
You would not read Psalm 50:10 literally, for example, unless you wish to assert that God is literally saying that the cattle on Hills 1,001+ belong to someone else. It is not a literal statement. You properly read it literarily: as a metaphor that means everything on earth belongs to God. Read it literally, and you're abusing it.
That is the teaching method of liberal churches.
It is part and parcel of the grammatical-historical method of interpretation, which I would expect to be taught at any responsible, Bible-believing college or seminary.
If he was advocating the grammatical-historical method of interpretation, he should have been more clear about it. Usually “LITERALLY instead of LITERARILY” is the war cry of those who want to deny a literal Adam and Eve, a literal creation, and a literal flood, among other things.
(There is no grammatical-historical reason to believe Genesis is talking about something other than real people and events, but the so-called higher critics like to invent and claim literary reasons.)