You are diverting the discussion. The main point of that comment is the ISP can inspect those packets just like if you use their servers (and probably by exactly the planned way to do it in the first place.)
With regards of privacy, Google's definition of what's identifying or not is very dodgy. From your own link, the permanent record includes the timestamp, domain, geolocation and ISP. That's a lot of information if you aggregate it.
Down-voted for posting a link to a privacy policy? Hmm. Ok.
My point had nothing to do with your ISP packet inspection argument (notice I didn't address it). I was providing a counter-point to the "Google is the largest advertising and user-tracking system online. I would only use those DNS servers as last resource." My comment was simply to refute your indication that Google might be associating DNS with advertising or user tracking. They don't.
Edit: Can someone explain why the down-votes? Do you just disagree?
They will still be learning a lot about users, just not adding that to their otherwise neat idea they have about who you are. You have two identities; they can track, study and serve each one, no probs.
With regards of privacy, Google's definition of what's identifying or not is very dodgy. From your own link, the permanent record includes the timestamp, domain, geolocation and ISP. That's a lot of information if you aggregate it.