We all want healthy outcomes. No one is attacking the notion of providing the means for patients to avoid poor health outcomes. What's actually going on is that not all of us trust the methods that some wish to apply, and with good reason.
The problem isn't with the statistical foundations (that's well-tilled soil).
The problem is that large-scale programs cannot be designed in a way that accommodates all individual circumstances and heterogeneity, leading to ridiculous or even dangerous "unforeseen" situations, as the O.P. describes. Anyone with an experience of bureaucratic administration of regulations and public initiatives knows this is a universal feature of them.
A bigger problem is that the well-meaning people who design and administer large-scale public health initiatives often believe that the science behind their programs is sound and settled. It's not. They act arrogantly or dismissively towards those who want more than authoritative statements to validate interventions in other peoples' lives. When those in charge believe they possess unassailable science, they stop thinking about how they could be mistaken, and instead, criticize or insult those who might question their pronouncements. As always, it's the skeptics who actually advance science, by pushing against this inflexibility.
Here are some examples of "settled science" that have recently been re-examined and found lacking in recent research. (This is intended for conversational purposes only. This is a discussion board, not a research journal.)
* Salt is bad for cardiovascular health. Right?
“…a meta-analysis of seven studies involving a total of 6,250 subjects in the American Journal of Hypertension found no strong evidence that cutting salt intake reduces the risk for heart attacks, strokes or death in people with normal or high blood pressure.” (2011)
http://www.scientificamerican.com/article.cfm?id=its-time-to-end-the-war-on-salt* LDLs are the bad form of cholesterol.
“The so-called “bad cholesterol” – low-density lipoprotein commonly called LDL – may not be so bad after all, shows a Texas A&M University study that casts new light on the cholesterol debate, particularly among adults who exercise.” (2011)
http://tamunews.tamu.edu/2011/05/04/%E2%80%98bad%E2%80%99-cholesterol-not-as-bad-as-people-think-shows-texas-am-study/* Saturated Fats Cause Heart Disease. Well, everyone knows that, right?
“We’ve spent billions of our tax dollars trying to prove the diet-heart hypothesis. Yet study after study has failed to provide definitive evidence that saturated-fat intake leads to heart disease.” (2007)
http://www.msnbc.msn.com/id/22116724/ns/health-diet_and_nutrition/t/what-if-bad-fat-isnt-so-bad/* More than a couple of drinks a day, every day, affects heart health negatively. No brainer, right?
“Drinking a bottle of wine a day, or half a dozen beers, cuts the risk of heart disease by more than half in men, shows a large-scale European study.” (2009)
http://www.independent.co.uk/life-style/health-and-families/health-news/drink-half-a-dozen-beers-every-day-and-have-a-healthier-heart-1823218.html*Being overweight will shorten your life. OK, now we're getting close to the specific topic of this thread.
“…in elderly persons followed for two to 23 years, a baseline body mass index (BMI) below normal (18.5-25kg/m2) was associated with a higher risk of mortality whereas a BMI above normal (>25kg/m2) was associated with a lower risk.” (2011 - multi year citations)
http://www.nel.gov/evidence.cfm?evidence_summary_id=250331I could fill pages all night with this stuff.
As I see it, scrutinizing public health initiatives may actually be doing more for positive patient outcomes than parroting the received wisdom, or prescribing one-size-fits-all approaches. Skeptical scrutiny is the soul of science.