Earlier quoted context omitted.
There are parts of my life that are fine for ad companies to know. What clothes I like, what music I like, what sports I like etc. These are all benign, and even useful to me if ad companies know about them. The sentiment of your comment makes sense when applied to these topics. But then there are things that I don't want ad companies to know about. My medical history, my likely voting patterns, my political affiliat…
You also don't know if in 10 years time the country gets a radical, religiously fanatical government, that will then order these companies to list users who are non-believers, have "wrong" sexuality or supported the opposition. When Nazis invaded a city, first thing they'd have done was getting to people register and getting names and addresses of "undesirables". People have not learned their lesson.
Evil regimes have never had a problem finding lots and lots of citizens to kill in the 99% of human history before the internet.