the sacred part is often tied into the history of the book , the edition, the tradition, the binding options, in some instances the rarity of the documented text, whatever.

I have many books that are heirloom items from generations before me, I would never write in them. They are a testament to their point in history, and altering them would be akin to defacing art in my eyes, depriving future generations from the beauty that I got to behold unsullied.

If we're talking about "Do you write in the margins for "C++ for Dummies 69th Edition", sure.