The White House probably realized very early that they were forgeries. They really couldn't come out and yell that they were forgeries because it would make them look guilty so they did a very smart thing...they released them to the public. The public, as we now know, also very quickly saw that they were forgeries. This was a brilliant move by the White House.
"They really couldn't come out and yell that they were forgeries because it would make them look guilty "
Why is that? At any rate, they didn't have to yell. They could have just phoned up CBS and told them they were forgeries, and that they would expose them as such if CBS used them.