Why is Google scared of other Affiliate programs?

Try searching for ‘Affiliate Programs’ in Google and the first in the list of Paid Ads is of…

Yes, Google Adsense.

So, why does Google need to run PPC for its Adsense Program for major keywords -

1. Affiliate Programs
2. Healthcare+Affiliate Programs
3. Top Affiliate Programs
4. Healthcare Affiliate Programs

…..Is Google scared of other Affiliate programs?

…..Is it fair for Google to outbid its competitors on its own paid network?