And that works because they are pretty much irrelevant right now. I doubt they could get aways with no presence in on of their biggest markets, if the reach something like 25-50% market share.
I think the point that the parent was also trying to make is that even if this would effect only Google it's still very important because let's face it, almost nobody uses DDG. At least in Europe and compared to Google.
90%+ of Europeans use google. How many use DuckDuckGo? So not having that stuff on google is pretty effective.
Who uses that stuff when looking up someone?