Because it cant accurately identify them. Frankly, I dont have much against Google having something against paid links. Its their search engine, they can do whatever they want with it. Of course Id prefer they live and let live when it comes to paid links, for my own self-interest as someone who occasionally uses paid links as a way to build incoming links for my SEO clients.
But the problem is theres no way for GoogleI should say no effective wayto differentiate between a paid link and one tha....

The Organic SEO