It would be possible to handle the quantity of ad campaigns, but not without false positives or missed fraudulent ads.
If you paid a person or a team of people to remove adverts promoting fake websites, the person reviewing the advert would have to understand the product being sold, the company selling the product and the companies real website. For Chrome this may be easy, but for more obscure projects such as a cryptocurrency wallet or email client it'd be hard for a person to distinguish between real and fake continually over the course of an 8 hour work day.
People who are searching for a product already understand that context and so will be able to make a less erroneous judgement on whether a promoted link is real or fake.