Of course, if somebody was studied in archeology and the Greek language, and had read and was friends with a variety of Greek and many other ESL scholars working in the field, perhaps their comments would hold more weight than total speculation. Despite all the contextual clues, since the words are there as they were written, I cannot state for a fact he did not intend for them to come across exactly they way they do to the ever-so-elusive "reasonable native English speaker".
That's not what I was saying. The words have a certain force by definition. The way they're used is a separate concern; it's possible that in another language, the correct academic practice is to use words indicating certainty while it's just understood that the certainty isn't really present. In such a case, he might accurately understand what the English words he's using mean - they convey total certainty - without understanding that English speakers will interpret them as conveying total certainty.