This is just disclosing that Google Voice collects information.
I’ve highlighted the paragraph in bold: Google claims the right, to log information like your phone number, date and time of calls, duration and also SMS routing information. A German site mobilsicher.de has tested it – during each phone call, Android tries to connect to a Google server.
It searches the number for better caller ID information I'm sure, and your Google Contacts. Google has access to a shitton of phone numbers from Google's indexing.
If you've ever worked in high scale deployments, you know that you generally will have HTTP logs of every connection even if you are some strict privacy site, so the "claiming the right" is more of just reducing legal liability even if they are trying to disable logging on every server (which they probably aren't, but they could be). Sysadmins make mistakes.
I'm actually going to give Google the benefit of the doubt on this one. That being said, if you are paranoid about this the way out isn't to ditch your phone entirely but just install a different dialer. Android is very extensible.