I don’t agree with the parent that the solution for SEO spam is paying for the search engine (I think there are other good reasons to do this though), especially since people have been doing things like naming their company “AAA Auto Repair” to be first in the phone book since before computers ever existed. But the person you originally replied to does have a point in blaming Google for the problem. Most SEO spam sites make their money from ads, and Google are the ones who run the ad network, which means Google are the ones funding them and creating an incentive for them to exist.