Irishwonder has put it very well: Google is using all of us to create the "invisible" filters and flags: It's everyone of us who is using there Disavow tool who is responsible:
Google has depended on user input in the past, they have been known for encouraging spam reports, paid link reports, feedback on various updates they were rolling out etc. – this time however, it’s much more serious. They are now instilling the view of links – any links – being dangerous in people’s minds, and links ARE the nature of the web, if Google disappears tomorrow the web will still be made of links, content and links between it.
But what are we to do?