It shouldn't. "Bible" etymologically derives from "book", and its meaning denotes an authoritative book, or "the" book on a topic.
While it is true that the "Christian Bible" has customarily been shortened to just "Bible", in principle it is appropriate to call any authoritative book that claims to be "the" book on a topic as a "Bible", without necessarily carrying any religious connotations.
That's not to say that people might not make that link mentally, but technically and etymologically speaking the term is not religious. In the same way that some people may no longer identify as gay=happy, but if you start getting offended about people acting having a "gay old time", then that would say more about your sensitivies than about how people choose to use the word in different contexts.
The common phrasing christians use is actually "The Holy Bible", with "Holy" being a common word in the bible meaning "set apart for God". So "The Holy Bible" is that particular "Bible" (book) which has been set apart for God.
In fact, calling it a Holy Bible implies there are Bibles which are not Holy. As one would expect, given a bible is just a book, in greek.
While it is true that the "Christian Bible" has customarily been shortened to just "Bible", in principle it is appropriate to call any authoritative book that claims to be "the" book on a topic as a "Bible", without necessarily carrying any religious connotations.
That's not to say that people might not make that link mentally, but technically and etymologically speaking the term is not religious. In the same way that some people may no longer identify as gay=happy, but if you start getting offended about people acting having a "gay old time", then that would say more about your sensitivies than about how people choose to use the word in different contexts.