For all that Google search has been utterly crap for going on a decade now, I have to admit part of the reason is that they get targetted relentlessly by SEO spam operations like this. I like DuckDuckGo for now, but I imagine as they get bigger they're going to be a target for these kinds of spam just the same.
Why, though? There is an arbitrary ranking system that seems increasingly independent of what I actually searched for. Google had created a game where the winner isn't necessarily relevant or at all useful. It's inevitable that spammers will play that game.