It's easy to see why Google banned these guys and not Amazon.com or Walmart. I could sum it up in one word: trust. Amazon and Walmart have it, these guys don't.

Personally, if I'm going to buy a knife, I'll buy it from Amazon. I trust them on a whole bunch of levels that I don't trust these guys.

Is it fair? I've been doing SEO / PPC for over a decade and its never, ever been fair.