How Is This Useful To Future Generations?

At the beginning of the film it's stated that a copy of this film has been placed into a time capsule so that Man of the far flung future might some day dig it up and learn about the hopes and fears of the Age of the Atom and think upon us, their more primitive ancestors.

Yet, the film also states that it has changed actual facts and made up others (such as people that did not exist). It even goes so far as to use fake people delivering the supposed pitch to our descendants.

If the story they have been told has been altered, how on earth are they supposed to learn anything from it? That's the worse history lesson of all time.

"Hey, something happened. Some of the stuff we're telling you is true, some isn't, but it's still super important that you learn from it, ok?" 😛