It wasn't out of the blue. This complaint has been ongoing for a long time. Regulators have been vocal about these concerns for a while. Discussion of these issues,such as how the ad industry is at odds with privacy activists and increasingly regulators too, are common across various academic and industry forums. Amazon will have taken expert legal advice and likely have been involved in lobbying at all levels. Regulators typically have carefully constructed action policies which cover a range of measures, including warnings, which may well be delivered privately. Not everything that happens in the world makes the front page of Hacker News :)