A Good Book
Everyone knows why Tennessee legislators wanted to make the Bible the state book. They wanted to send the message that you're not welcome there if you're not a straight Christian conservative. And um, 1925 called, and we got the message.
However, to sell the idea, the lawmakers used language of the state's "history" and "culture". Not only are they using the language of a fancy person who's "spiritual but not religious". Effectively, they are saying the Bible is special because of its significance to the state.
Tennessee's relationship with the Bible is resembling China's rekindled interest in Confucianism.
In that vein, I'm sure the bill was mostly about education, people wanting Christianity taught in public school. Under the rubric of the Abington vs. Schempp decision, religion needs to be presented without favor or disparagement. Maybe the legislators wanted to give the Bible a leg up in this framework, but they did it in terms that suggest it's part of a common heritage, and were it not for the favor of the government, it would be just another book.