Perhaps that's what google want you to believe, much like how Target scared people off with their targeted (heh) marketing that outed, among things, that a teenager was pregnant due to the things she started buying. After those events, they started inserting random ads to give a plausible chance that the very-targeted ads were random.

https://www.forbes.com/sites/kashmirhill/2012/02/16/how-targ...