I think you misunderstand dark pattern here. If you sit and think about it for a while, then yes, it makes perfect sense. But the point of a dark pattern is to give quick, hurried users a misconception of what the choice is.

The non-dark pattern here is to say "Ad Tracking - On/Off".

http://www.theverge.com/2013/8/29/4640308/dark-patterns-insi...

BTW, Google lets you opt out of Interest Based Advertising: https://support.google.com/ads/answer/2662922?hl=en