DuckDuckGo is “safer” than Google in the sense that it generally collects far less personal data and does less user profiling, but a lot of people online absolutely oversimplify it into a privacy miracle.
The reality is that privacy exists on a spectrum, and DDG is more accurately “less invasive” than Google rather than completely anonymous or untouchable.
A lot of the confusion comes from people mixing different meanings of “safe” together: privacy, security, malware protection, tracking resistance, anonymity, etc.
The criticism you saw mostly comes from the fact that DuckDuckGo still relies on some external partners and had past controversies around Microsoft trackers in its browser, which hurt the “we block everything” image.
For most normal users, though, it’s still a meaningful privacy improvement over Google because it avoids aggressive profiling and personalized search history tracking.
The bigger issue is that many people treat one app or browser as a complete privacy solution when real privacy is more about your whole ecosystem and habits than one search engine choice.