Please, ever heard of stomach acid? While it best to send your food down in smaller parts, you could eat a big enough "raw" piece of food and your stomach acid would still tear it apart. Although, admit it may give you a stomach ache or acid reflux. Still, the acid will desolve it enough to flow through the intestines.
BTW, although there are probably too many extra ingredients in our foods (most for preservation), "raw" food is a fallacy. People have been living longer and longer if they just eat a normal/balanced amount of even processed foods. That's not counting medical care.
Yes, it destroys the nutrition of grain. Stomach acid is used to digest things like road kill or large quantities of any kind of food. But when we eat very small quantities of grain, stomach acid is not supposed to be involved. I say "not supposed to be" but obviously most of us have done the vast quantity thing for so long, the stomach acid comes automatically even if we don't eat anything.
Although, admit it may give you a stomach ache or acid reflux.
Yes, by eating incorrectly for our whole lives we get excess stomach acid. Some people get stomach acid when they don't eat anything (e.g. sour stomach in the morning). That is because their body expects them to eat something through years of training. Like nearly everything else in our bodies, stomach acid is triggered in the brain.