I never cease to be amazed at the number of people who make self-validating proclamations about what Google does or doesn't do, without having any information to support their positions.
I guess I'll say what I always say: Look at the public privacy statements for Google, or for a particular Google product. If you have any evidence that Google does anything different from what's in that statement, contact Google and there will definitely be people interested in figuring out what's going on and fixing it.
Why do you think you know how it works? What do you actually know about Google that doesn't come from outside speculation?
That link says that a website leaked an IP address to Google. It doesn't say that Google did anything with the IP address.