The "rapidly absorbed" qualifier is an allusion to this. Fiber has several benefits, one being blunting the spike in blood sugar by slowing absorption.
Some foods are healthiest when unprocessed (other than the minimal processing involved in harvesting and shipping), but bioavailability of nutrients in others is greatly improved by cooking and/or other processing.
Certainly, the safety of most meats is greatly improved by cooking.
The point of the naturalistic argument is actually a good one. We keep pretending we understand all the mechanisms and yet we get baffled over and over when we do enough processing and even though the ingredients are all still there it turns out there was one more thing we weren't aware of that completely changes how we react to the food.
trying to guess what vitamins or whatever are missing from a demonstrably deficient diet is not going to beat a known wholesome diet, even if your worldview for some reason contests the existence of a 'known' 'wholesome' diet
I mean, I would really like us to fully understand nutrition, and I'm optimistic that we eventually will... its just that we don't, right now. Not really.
sugar in nature is almost always paired with fiber, separating them makes the sugar much more harmful