On the specific issue of saturated fat and heart disease (saturated fat isn't the only problem fat -- trans fats are also an issue), its been shown to be more complicated than earlier thought; there's pretty strong evidence that certain high-saturated-fat foodstuffs are associated with higher risk of heart disease, but some large scale studies that seem to indicate that saturated fats overall do not appear to be (and there is some indication that certain saturated fats may actually be beneficial to an extent.)
But you've given away Scott's point. We've been listening to how bad saturated fat is for my entire lifetime pounded into the public with the maximum volume science has available to it at the highest governmental and science authority levels, and now, oops, mea culpa, it's more complicated than we thought, and right now it's not exactly out of the question that "saturated fat" will be entirely removed from the "bad thing" or even "consumed too much by Americans" column in another 10 to 20 years.
No matter how upset you get about people being a bit glib about what the consensus said (and frankly I'm not sure I couldn't establish "science said saturated fat is bad, full stop" with just a bit more effort than I'm willing to put in right now), you can't get out of the fact that the pounding was apparently unjustified, and there's a nontrivial chance it was flat-out wrong. Science and scientists shouldn't expect to escape from those decades of being wrong at maximum volume and the corresponding vicious evils inflicted on the world (because after all the US consensus has been exported all over the world), and it would be utterly and completely irrational for me not to update my beliefs based on this evidence.
Further one doesn't need to look very hard to find "proof" that the "fat = bad" message is prevalent in society.
Go to the grocery store. Go to the dairy isle. Look at the various products. If you can't find "low fat" or "light" versions of most of things there, I would be dumbfounded.
If major corporations have picked up on the "low fat" movement then I think it's fairly safe to say that it's prevalent in society.
The whole reason trans fats were invented or added to food is that food manufacturers needed a hard fat with the properties of animal fat that came from a vegetable source. The reason for that is scientists claiming that animal fat was bad for you.
No, actually, trans-fat heavy vegetable-based fat products were invented for cost reasons around three-quarters of a century before saturated fat concerns began, and saw a big upswing in popularity in the early post-WWII period more than a decade before the research indicating that saturated fats were potentially a heart-health risk factor.
Its true that once the health concerns about saturated fats first started appearing, the marketing of margarine and related products leveraged it to imply that there product was more healthy, but that's not why those products were invented.
On the specific issue of saturated fat and heart disease (saturated fat isn't the only problem fat -- trans fats are also an issue), its been shown to be more complicated than earlier thought; there's pretty strong evidence that certain high-saturated-fat foodstuffs are associated with higher risk of heart disease, but some large scale studies that seem to indicate that saturated fats overall do not appear to be (and there is some indication that certain saturated fats may actually be beneficial to an extent.)