If you search for tank man on DDG, the very first result is the Wikipedia article about said individual and the Tiananmen Square massacre. If they were intentionally trying to censor the search results, why would they only censor images?
I don't think DDG is trying to censor results (nor that the parent post is suggesting that), I think they're inheriting censorship from their upstream sources, which aren't the same for different search types (web, images, news, etc.). Interestingly, it seems that even starting to type the "man" in "tank man" will result in no suggestions at all, even though the web results seem reasonable.
