First of all, the NEC has nothing to do with right and wrong, it’s a fairly well-designed document based on engineering, that’s all, and it cannot possibly cover every situation, nor is it infallible or all inclusive, which is why it’s rewritten every 3 years.
So in those areas where the NEC is partially unclear, industry standard methods and what is traditionally approved has as much weight as the NEC.
I don’t care what the book says, NM has been, and will continue to be, terminated in exterior boxes. Every electrician in this country who works in residential, and every inspector who inspects residential installations, understands this.
You however, are free to wire as you please. That doesn’t make me, or the tens of thousands of other electricians, wrong, nor does it make the NEC the Holy Word, written with the Finger of God. Its merely another pretty decent document based on imperfect engineering and educated guesses.