Ok, I'm going to call stupid right off the bat. No; just ignorant, and this includes some top names. Why? I figure it like this: if Dean Ornish, Joel Fuhrman, John McDougall, T. Collin Campbell and others are ignorant about this when little ole' layman-me can find this info 'cause I look, then what? Do they prefer pricks & crooks?
This shouldn't take long. I'm going to give you a single word: Butyrate. The highest source of it in the diet is butter, particularly rancid butter. And guess what else? It's a short-chain saturated fatty acid. It's saturated fat (OMG!). ...Whew, the vegans, veggies & high-fiber priests can take a breather. Is that all? Finished now? Was it just a disjointed, out-of context rant, or what? Well, no; but I'll get to that later.
First, let's realize that much of the veggie, vegan, high-fiber (there's your BIG CLUE) catechism is designed to appeal to those who want to loose weight. How many commenters here have you read who tried the veg / vegan approach to fat loss before they went paleo? Lots. Experiences ranges from added weight gain to weight loss -- but with diminished well being. (I realize those who get good results don't typically comment here; so, yea, selection bias.)