still, you'll notice I did not say the evidence is uncontroversial in every respect - I was speaking in general terms, and in general terms, the evidence that not breastfeeding produces negative outcomes is not weak, or controversial at all....in all settings, developed and developing world.
This is not 'spin'. It's actually important stuff - the stuff where the evidence is strong, as you acknowledge (principally breast cancer, gastro and chest infections but there are several others) makes a difference to the quality of life of many families in this country...yes, on an individual level.
The research 'problem' with any health behaviour in individuals is that you cannot point to one single behaviour and say, for certain, 'X caused Y' , and I'm including smoking and alcoholism in that.
The evidence that smoking causes lung cancer and alcoholism causes liver disease is 'only' epidemiological and retrospective anyway - you can't randomly assign people to smoke or drink. You find out that 'excess' mortality and morbidity occurs in smokers/drinkers, and work backwards from that.
However, there are people who show no ill effects of smoking and drinking, and who die age 90, so clearly the links between smoking and drinking and poor health are more complex, in individuals, than a direct cause and effect.
You say "not breastfeeding is unlikely to make any difference on an individual level to health." That's a totally illogical statement. Epidemiology is a collection of observations from thousands of individuals.
What I think you mean is that 'we cannot ever be sure what difference breastfeeding is going to make to any individual' and of course that's as true for breastfeeding/formula feeding as it is for smoking and alcoholism.
Note for the very literal-minded: I am not saying that formula feeding is the same as making your baby smoke or drink alcohol.