InfoUSA & the Do Not Call list.

I looked up InfoUSA.com regarding tapping into email lists for business purposes. I accidentally hit the "calling list" button. This came up.

Why does InfoUSA.com make a point of asking you if you want to include the Federal Do Not Call phone numbers if those numbers will be excluded from the calling list you purchase?

I'm confused. Isn't it assumed these numbers won't be included in your list of phone numbers?