And find but these books that explain the nec should explain this and not just make a statement
It seems like you have all the answers but I promise you, you don't. There are reason for many things in the code and because we may not know what they are doesn't mean that there is no reason. I agree the white wire rule is strange but it may have been put there for some reason years ago and now it remains.
If you think all the nec stuff is bogus then I invite you to come up with some substantiated changes and make comments to the nfpa for the next code cycle.
We all can complain about some of the rules and sometimes it does seem ridiculous but there is only one way to deal with it and that is to make a code change which anyone is welcome to propose.