There is a Russian expression "из песни слова не выкинешь", literally "one cannot throw a word out of song".
The meaning is that "when telling a story, one may not omit even unpleasant/unsavory details":
...during the interview he bad-mouthed his previous employers, he even call his former boss (sorry, one cannot throw a word out of a song), a 'bitch'...
or, more broadly, "a coherent structure loses its coherence when critical parts are removed":
...to prove this lemma, we need to consider seven cases; this is somewhat tedious, but one cannot throw a word out of a song, so let us begin with...
What is the English analogue of this expression?
Russian proverbs offered no "English equivalent" (I now added one, see below), just
Meaning: You cannot alter the information that many people know by heart. — Also: The following may contain obscene, rude or otherwise questionable content, yet it content cannot be omitted as it's an integral part of the story.
What I tried: