Websites like this want traffic from Google. To get indexed by Googlebot they have to show the bot the article text, and Google's anti-blackhat-SEO rules mean t

Websites like this want traffic from Google. To get indexed by Googlebot they have to show the bot the article text, and Google's anti-blackhat-SEO rules mean that you have to show a human clicking through from Google the same text that you show Googlebot. So they have to show people visiting through that route the article text too.