This is no longer the case as of August last year, they managed to get the terms of the agreement changed https://www.pcworld.com/article/828064/duckduckgo-will-now-block-microsoft-trackers-too.html
Edit: Duckduckgo's statement on it https://spreadprivacy.com/more-privacy-and-transparency/
The funny thing is I wouldn't mind watching their ads if they weren't annoying with them. If the ads were only at the start of a video, not during, and no still image banner at the bottom I have to click X on on desktop. I don't want to actively dismiss anything while I'm watching the video, I want to relax and watch it.
They don't allow me to sit and enjoy the videos without babysitting them to skip after the timer, so that's why I block their ads with absolutely no compromise anymore.