Why do you suppose the only book BB permits the HGs to read is their Holy Book of record, be it the Bible, the Koran, the Torah or what have you...

Constitutionality doesn't enter into it because they aren't a government entity and they aren't entitled those rights. More likely it makes religious people have folks to root for and allows them to feel less guilty about watching the show in general.

I believe that they give these items to them as a way to give the house guests a way to ground themselves, not so much to bring themselves back to a moral place or to show that they are hypocrites, but merely some sort of way that they can come to a place of solidarity within themselves. Everyone has their own beliefs. For some, it may be religion. For others, it may be another form of meditation. There are other aspects of the house that offer grounding experiences as a privilege, but they must win those items via competition. (ie: HOH: letters from home, pictures, snacks, etc)

Just my opinion... :)

They only allow the Bible/Koran/etc. because if the houseguests read aloud from them, CBS doesn't have to pay anyone a royalty. It's the same principle as not allowing them to sing.

They should allow Shakespeare's entire works in there too -- they wouldn't have to pay for that either, I believe.

I believe a bible must be available. BB doesn't want other books because it would cut down on conversation and mingling time. When bored, houseguests would just go rooms and read.