OST is closed for business but its spirit survives on my blog.
Isn’t the word “rightly” taken from 2 Tim 2:15? “rightly dividing the word of truth” in the KJV which is what many conservatives grew up reading. If you’re asking why they use the words rightly and proper, I think that is the reason. The TNIV says “correctly handles the word of truth.”
To the question whether or not there is a “proper” understanding of scripture I would need to know your interpretation of 2 Tim 2:15?