You are insinuating that the collected data leaves Google's servers and enters the advertiser's servers.
It does not.
Google's business model is: give ad banner to Google, fill out a form specifying the desired demographic targets, done. Google then stores the banner on their server and their server sends out the banner when a user matching the chosen demographics views a page with Google backed ads on it.
I am insinuating nothing of the kind. If you read what I have said and what you quoted I have not stated that Google passes personal user details on directly to the customer. That categorised data becomes the product which Google sells via their advertising program. As you have said, they sell targeted advertising and without user data supplied via interaction with their services there would be no product for them to sell. I would be interested to know how you know exactly what Google does with the data they collect however. Perhaps you work for them?