[zzo38computer]

Your reasoning makes sense. However, it is not quite that simple.

As another comment mentioned, "and yet Jehovah's Witnesses are denoted on the list as a Christian faith".

So are Quakers (also denoted on the list as Christian), which (as far as I can tell) have no creed ; and, furthermore, although the Religious Society of Friends is Christian, not all Quakers are necessarily Christian (there are people of other religions as well, as well as those of no religion).

This does not seem to be specific to the DoD list; I have seen this in other lists as well.