Trying to reduce something as multifactorial and complex as thrombo-atherosclerotic disease down to one identifiable process is a straw man's argument. It's not really fair to say fat has nothing to do with it. If that were true, different dietary fats would not have different effects on atherosclerotic plaques (olive oil, fish oil, etc). Besides, human patients with mutations in different fat pathways definitely have serious CV complications. But fat is far from the only factor.
I'm guessing tertius probably meant "dietary fat consumption", although you're right that definitive statements are almost always wrong (see how I didn't make a definitive statement ). I also don't think it's fair or necessarily beneficial to include rare genetic mutations/diseases into the general discussion. There will alway be excepts to the "rule", but that doesn't mean we disregard the "rule".