See, Mozilla’s web warning is provided by Google. And why Mozilla doesn’t check all websites themself?
That is iwarg’s false positive btw
If they did, it wouldn’t be very good. Detection of unsafe sites is difficult, you’re dealing with criminals who are going to do everything to avoid being detected. You need the resources of antivirus detection, AI models for phishing, the browser marketshare for reporting, and all the other infrastructure for it to work well.
At present, I think Microsoft and Google are the only ones who have the means to make this work.
Google pays most of Mozilla’s bills, so it makes sense that they would use their service.