Your attitude is exactly what the parent comment is describing. You have the benefit of decades of scientific research and government mandates that didn't exist for previous generations. Modern cigarettes date to the late 1800's but the link between smoking and cancer wasn't established until the 1950's. It took over a decade after that for the first warning labels to appear on packs, and the photo type you're describing didn't exist until the 2000's.
It seems obvious to you because it has been made obvious to you. It wasn't the same for people in the first half of the 1900's. The parent comment is making the same point: it's not obvious to most people today, but in fifty years from now, people will look at the research, the decline in the birth rate, the increase of anxiety, and effects we can't imagine today and go "social media has very visible side effects fairly soon, how did they not know?"
It seems obvious to you because it has been made obvious to you. It wasn't the same for people in the first half of the 1900's. The parent comment is making the same point: it's not obvious to most people today, but in fifty years from now, people will look at the research, the decline in the birth rate, the increase of anxiety, and effects we can't imagine today and go "social media has very visible side effects fairly soon, how did they not know?"