Alright. Let’s simplify it, then.
The Church teaches that there are two senses of Scripture: the literal and the spiritual. The literal sense is what the human author intended. The spiritual sense allows for a meaning beyond the literal sense.
Now, there are a few types of spiritual senses. One of them is the ‘allegorical’. By this, we mean that we see elements of Christ’s life in a wide variety of Scriptural events.
The Church teaches that it’s possible for a passage of Scripture to have both an interpretation of the literal sense and interpretations according to spiritual senses. The author whom you brought to our attention in this thread is claiming that, if there’s an interpretation according to a spiritual sense, then that’s proof that early scholars did not seek interpretations according to the literal sense.
SImply put, this scholar is mistaken.
Does that help?