At its scale google could just hire a big group of diverse internet-aware professionals (two of each kind) who would do random searches and simply manually ban sites that restyle or spam content. It’s absolutely easy for a searcher to tell if it’s spam.
This is actually an interesting rabbit hole. Their other constraint is that they are trying to be transparent and fair, for some definition of that word. They need that for Section 230 protections, they need it to fend off antitrust lawsuits, etc.
So, there is a huge problem with hiring experts and telling them to make subjective decisions. Instead, Google publishes guidelines for webmasters and then enforces them rigidly. This usually ends up penalizing some good sites, while spammers swiftly discover workarounds.
then make it a gov position, like the "Beer and Malt Beverage Labeling and Formulation Approval" position, which consists of a single guy approving or rejecting the graphic designs of beer bottles/cans. there was an NPR segment a while back about the one guy that held that position for 40 years.
