You're arguing Google has sensible motives. That doesn't particularly matter. What matters is what they encourage website owners to do in practice. Apparently that is to fill your website with worthless junk text.
My point is that Google has sensible motives, and that people with perfectly good sites will butcher them in the hope of making a buck, and then blame Google.
Google doesn't "encourage" people to butcher their site. Google has determined the kind of property they want to advertise on.
The owners of the site make their own choices. If they choose to game the review process then that's on them, not Google.
The owner now has a crappy site, which is still a bad place for ads (although the review doesn't know it.) The ultimate goal, of getting revenue, is perhaps still unrealized.
Google has sensible motives but, undoubtedly owing to a lack of strong competition, they are not very good at serving these motives.
The fact that AdSense can be gamed incentives gaming. Unlike Google, websites like these DO have competition, and so the ones that game the system most effectively make profits and the ones that operate most ethically go out of business.
If Google does not want AdSense to be gamed, they should close the loopholes that make it so easily gameable and that punish honest customers. However, they are not strongly incentivized to do this because neither websites nor advertisers have any good altetnatives, so they aren't meaningfully losing business over it. And so funds that could go toward fixing this are, instead, used in areas that need the funding more urgently.
Assigning fault here is silly. The websites could be better AND Google could be better — but they will not become better without the right incentive structure.
