Today, the Colorado Supreme Court became the first state supreme court in the country to address the constitutionality of a keyword warrant—a digital dragnet tool that allows law enforcement to identify everyone who searched the internet for a specific term or phrase. In a weak and ultimately...
Your statement contradicts their stated policy, and I'm not aware of any such requirement in the US.
https://duckduckgo.com/privacy
IP retention is addressed in the first paragraph under "privacy policy", and it stated they don't save or log it.
How do you know? You don't control their servers
Your point is not unique: all websites require your trust.
So if that's your threat model you can't use any search engine.
But if we want to put that aside and discuss their stated policy, then the link I provided addressed the parent statement that
Which directly refutes that there is any such requirement.
You shouldn't trust any search engine. That's my point.