Except it is about us too sextrainglue.
Some of the examples quoted upthread are disgusting. I know of absolutely nobody in their right mind who would condone what certain formula companies did in the past and the impact it had on breastfeeding in developing countries. Of course measures should be taken to stop that happening.
But I still don't see that as a reason to take the anti formula rhetoric to its furthest possible extension and claim it's ok because it's just the thin end of the wedge and we have to do it because "we need to unite to stop babies dying".
I know personally of three women who have had PND, one extremely seriously, after trying and "failing" to breastfeed, and I think I was lucky not to get it myself. How you feed your baby has become so emotive, with formula feeding so thoroughly painted as "second best" at every possible turn that many, many women feel incredibly guilty and that they've let their babies down when breastfeeding doesn't work out for them.
As you've said, we would never extend this thin end of the wedge logic to other health issues (and my example wasn't just about "sub optimal diets in the western world" anyway, I think that's somewhat minimising the massive impact of obesity and diabetes on individuals and health systems worldwide). But as long as it's in support of the relentless pursuit of breast is best, it's all ok.