[Kip Russell]

True, but it’s not A bible, it’s THE Bible. Even many supposedly educated writers do not seem to know the difference.

I'm not sure I see your point. Are there not times when saying "A Bible" is correct? Example:

"There's a Bible on the bookshelf, and another on the table".

Could you clarify, please?

[b9]

From the Merriam-Webster site:

uncapitalized:
--> : a publication that is preeminent especially in authoritativeness or wide readership <--

The Bible is always capitalized, but when merely referencing an authoritative, widely accepted publication as "the bible" of (whatever) it's not capitalized.

Hope that helps.