Having spoken to Gabriel offline, because I was building my own search engine, he cares quite a bit about this issue. A ton of us in tech clain to care about privacy, but very few of us put their balls (and actions) where their beliefs are. DuckDuckGo's privacy policy has been in place for quite some time. And, it's only been recently that he's advertised it.
And so could Microsoft, Mozilla, Apple, and Opera.
As others have mentioned, this is a good marketing move, but it's not clear to me that you actually care that much about this issue.