Isn't the point of a Do Not E-mail list to make it public and then put the restriction on it of not e-mailing anyone on that list? Otherwise, it is worthless to have such a list if the spammers don't even know who not to spam.

The spammers wouldn't have to steal the list - it would be given to them. So, the whole thing is used against everyone when non-USA residents download the list and add it to their to-spam list