Everything is optional. You don't have to be signed in or using cookies to search using Google.
That's how I like my information privacy. My only issue is the lack of encryption in gmail (and email in general).
Personal privacy is the users responsibility. There's a technology knowledge gap regardless if the user is using google or any other site. That isn't one websites responsibility.
It's kind of a classic trojan horse. We will provide you with this awesome service, and get nothing in return. Nothing in life is truly free, it always come with a different motive. People can't turn down anything that's free. Especially people in the US Of course people should have a right to know what depths your analyzing them, but particularly in the US people don't seem to care as long as they don't have to pay for it.