To keep Google's monopoly in check. Google has exerted way more than its legal power to manually remove sites from its search results. Once removed, it means you don't exist. No entity should have that kind of power in denying people's freedom of speech. Manually action to remove sites is pure evil. With their world class engineers, scientists, billions of capital and years in the field, if they are not capable of algorithmically rank sites, then they have a problem.