Because they are not related. You can use them just as you would with Google Adsense. Obviously you can get a lot of free advertisement and edorsement with having people "like" you on Facebook, but that is beside of the point.
And the click scam, if true, will take away the only way for Facebook to monetize the product. Marketers are not stupid, things like this spread like wildfire.
Obviously the news here is not the loss of business for Facebook, but the fact that a click scam was taking place (if true).