I don't understand this style decision in web page design. I don't want to read content like a receipt from the grocery store. I instantly go to Reader Mode i

I don't understand this style decision in web page design. I don't want to read content like a receipt from the grocery store. I instantly go to Reader Mode in my browser when I see pages like this. Is this because of phones? Why can't it adapt? My 42" monitor wants to know.