help me understand

On NPR I heard a blurb about a national do not call list. And while, please don't get me wrong, it seems like a great idea, I don't understand the method for going about creating the list.

From what I heard there is currently a URL you can go to and add your name, thus letting it be known that you don't want telemarketing calls. For those without Internet access, this summer there will be a toll free number where you can call and give that information.

Now, I understand about creating jobs and revenue and trickle down, and all. But please tell me that the list of people who actually WANT telemarketing phone calls would be shorter(I understand that it would not be null) than the people who DON'T want telemarketing phone calls. That said, why not do it the other way around?

Or again, am I missing something?