Millions of years of evolution went into creating human bodies that exist to a large degree on animal protein and fat. It’s only in the last 12,000 years or so that we’ve become farmers, and carbohydrates have been able to become the main fuel for most people. Natural selection says - eat your fat, it’s good for you.
Without getting to into the weeds, in the early 80's I spent a few weeks with some real earthy crunchy granola types, macrobiotic, etc., the whole shaboygan. In conversations with them, they had no problem with meat if you chose it, but their discussion of fats was interesting. In regards to oils and margarine etc. they said, look, a good mechanic knows the difference between a fine motor oil for his engine and grease. That last line has stuck with me all these years. When they cooled they preferred real butter and if I remember correct they used only olive oil. All I can say is pass the butter please :-)...