This is the case on Linux Mint. I can't even set Google as a search provider if I wanted to! Too bad Duck Duck Go is simply re-branded Bing results, and they kinda suck.
"In fact, DuckDuckGo gets its results from over four hundred sources. These include hundreds of vertical sources delivering niche Instant Answers, DuckDuckBot (our crawler) and crowd-sourced sites (like Wikipedia, stored in our answer indexes). We also of course have more traditional links in the search results, which we also source from a variety of partners, including Oath (formerly Yahoo) and Bing."
