Perhaps you were credited with enough sense

to search further when something that will eventually affect every American is brought to your attention.
The prefatory remarks to the post seem to include material from many sources; I have researched this myself.

1) They have removed any mention of Thomas Jefferson, the instigator of the "separation of church and state" doctrine.

2) The link provided specifically states that they claim "the founders may not have intended for a complete separation of church and state."

What else do you need to know?

Fact: Texas orders more school books from one source than any other state.

Fact: Most publishers prefer not to print more than one version of a book.

Fact: Put those two facts together and you can see that what is printed for Texas usually is the version that is sold to the rest of the states; it is cheaper and easier for publishers to print a "one-size-fits-all" textbook than to alter the book several times according to how fucked-up the individual state is. And that WAS mentioned in the link.
BBC's only real error was in condensing the material; had they gone into more depth you would have seen how dangerous a precedent this is.

Do yourself a favor; search the net for it yourself.