The subject of the article says as much about the politics of science as it is a comment on the science itself. To the extent the findings have been ignored, or perhaps even shunned, is not at all unique. Many important advances in medicine had a notoriously difficult time being accepted, as an example, the idea that bacterial infection was the cause of stomach ulcers had been around for decades before gaining traction.

I think the substance of the science discussed revolves around the composition of dietary fat. As the article notes, the recommendation for increasing the proportion of "polyunsaturated" oils is likely a major factor. Indeed, common vegetable oils contain a high proportion of linoleic acid, the "base" omega-6 dietary source. It has been shown in numerous studies that the omega-6 (N-6) to omega-3 (N-3) ratio is important since these essential fats are linked to immune system functioning.

N-6 fatty acids are associated with pro-inflammatory factors, N-3 primarily leads to anti-inflammatory products. In the archaic/traditional diet, N-6 and N-3 were present in roughly equal proportion, but with marked increase in vegetable oil consumption, N-6 to N-3 becomes "imbalanced", e.g., 10:1.

Inflammatory processes are well-known to play a role in cardiovascular disease, so it's not hard to see how increased N-6 fatty acid intake is a contributor. However this info has not been a secret in the fields of obesity and metabolic disease treatment and research, where the impact of dietary fat intake has been discussed and published for more than 20 years.

Since the mid-90's I've recommended sharply reducing polyunsaturated vegetable oil intake as part of "lifestyle" changes supporting optimum health, particularly for patients with predisposition to metabolic disease. FWIW I've followed my own advice for at least as long, the results have impressed my internist who jokes that I've become quite an uninteresting case.

(Don't have references at hand. If anyone wants I'll post them.)

Edit: grammar!