The grandparent post's content was deleted, but it pretty much said that the main reason Pinterest serves "spammy" results (where clicks don't lead to the clicked image) is because Google doesn't send them additional metadata telling which image was clicked.

Instead of fixing the structure of their goddamn website, they wanted Google to give them special treatment.

Btw, I agree with you however that Google serving garbage results was 100% Google's fault, though.