Correlation != Causation. The obesity issue has many factors (Quality of food; sedentary lifestyle changes overtime etc), the access to weighing scales actually helped with reality checks for most people.
No. If we needed a counterfactual claim for everything, you could also claim that maybe scales made people fat, because we weren't fat before we had scales....
And I'm sure some will take that argument. I'm not running a debate club.
I think you're making the point for me. The "reality checks" haven't helped people to improve their health.
Data != Action.