Natural fats are healthy. The body knows how to process them and expel them. "Manufactured fats" such as hydrogenated fats the body doesn't really know how to process effectively, so some percentage of those hydrogenated fats are kept and stored.
Hydrogenated fats, along with processed sugars and processed starches have contributed much to this country's obesity problem.
Atkins diet removed those very things shifting to a protein based diet and natural/organic fruits and vegetables.
Think of it this way: if you're eating something that's NATURAL, your body knows how to use and process it. If you're eating something that's manufactured/processed not so much.
Oh, I agree with everything you say. The whole “fat is bad” meme is just wrong. Our bodies need fat.
Personally, I don’t cut out carbs altogether; that isn’t healthy, and I believe it’s a type of fad dieting. But I do limit them. I’m definitely a carnivore.