You make a philosophical point while the reality is already clear enough. Everyone has a friend with kids so they hear the stories. The “scary” ones stick longer than the nice ones because it’s easier to understand financial woes, health issues, and problems of this kind.
I agree with you.
Most people can be sick and not see it because they are surrounded by other sick people. To them, that baseline of health feels healthy. You won't even really know why certain other people may cry, and smile, and laugh so easily and you can't. Maybe you received conditioning and beliefs about it in your environment which molded you into the sick person you are, and the other healthy ones are the sick ones to you!
People buying more chocolate ice cream than vanilla? Could be changing preferences or Hersheys marketing, or it could be undetected brain worms. People voting for one political party over others? Could be that party is campaigning/governing in a more popular way, could be brain worms.
If there’s evidence of contaminants or whatever influencing behavior strongly enough to change large scale demographic trends, then present it. Otherwise, your best chance at good data is to take people at their word when they say why they do things.
and, the latter is indeed dependent on the former. but, arguing that humans have no free will is an argument that should be tried independently of rebutting the former comment.