What are you talking about? Do you not see the giant, golden "Ad" next to each ad?
Sometimes I feel sorry for the advertiser when I accidentally click such sneaky text Ad, especially when the first real, natural search result is the link to the advertising company's website, just below the Ad. It feels like a devious way to rip off advertisers who would have been first anyway.
However, they are also blocking a competitor from placing an ad there and potentially siphoning off traffic.