Recently I read that the color that I call pink (light red), was not long ago not labeled as "pink" but as yellow. You can read some of the history as to how it became that pink and yellow are related here. The leading theory is that Queen Elizabeth loved carnations (which were originally only in light red/pink color). Carnations were commonly called "pinks" and thus associating the label "pink" with the reddish hue we know today. Fancy people might know the color "Dutch Pink" is yellow.
This silly example is just to point out the need to be suspect with any claim that assumes the current statement has always been interpreted the way it is currently being interpreted.
If we have changed our minds on what we interpret to be pink, then rest assured we have changed our minds on what we interpret the scriptures to mean. Just as there has never been an unchanging understanding of the color pink, so too there has never been an unchanging understanding of Scriptures.