You've been drinking the Google kool-aid. Google has always been the primary financier of web spam on the Internet. They knowingly profit from Adsense on spam sites. If they wanted to, they could end web-spam over night by banning Adsense accounts for spamming.
SEO is just another form of marketing. It is no more/less legitimate than PPC campaigns. In fact, PPC ads are far worse because Google does little to police them. As long as Google makes money, they don't care if you scam users. That's why they paid half a billion dollars in a settlement to the FTC for knowingly selling illegal pharmaceutical ads.
Like it is that simple. There are millions of adsense accounts. You can't hand pick everyone. Penguin 2.0 was supposed to hurt spam sites and judging by the fuss it created in Blackhat SEO sites it succeeded a lot.
They will manually remove sites for spam in their own search engine, but they don't ban the associated Adsense account. In other words, they are more than happy to pay you to spam other search engines.
Couldn't agree more. I run a small website and was ranked within first 10 results for some keywords in the past, because my content is very relevant to the niche and I did a lot of research to write it.
In the recent year or so, I have been pushed to 30+ place and top 10 results are completely useless junk websites that contain all the SEO and keywords, but really, really shallow information. I guess someone used Mechanic Turk or Fiverr to get someone to write about it for $5 and then slapped all the possible SEO stuff and now ranks well and earns money from AdSense.
Or maybe I was just punished because my website does not have AdSense on it...? I hope not.
Because they pollute the real results. If you write your content for search engines and not for users then it's bad content.