The study that your article references is a mouse study, so the relevance to humans is questionable.
In addition, fiber is shown to be beneficial to humans primarily when comparing the standard American diet to a high-fiber diet. This is likely because fiber is mostly non-digestable by humans (as we’ve lost the ability to digest fiber more than 2-million years ago unlike our closest living great-ape cousins), and acts as a physical barrier to the absorption of sugars and starches which also helps to lower insulin spikes.
If you do not eat a high-carb diet (such as a ketogenic diet), then eliminating the undigestable matter (i.e. fiber) from your diet is probably beneficial because you’ll be able to absorb more nutrients and get rid of constipation-related issues.
Dietary fibre is that part of plant material in the diet which is resistant to enzymatic digestion which includes cellulose, noncellulosic polysaccharides such as hemicellulose, pectic substances, gums, mucilages and a non-carbohydrate component lignin. The diets rich in fibre such as cereals, nuts, fruits and vegetables have a positive effect on health since their consumption has been related to decreased incidence of several diseases. Dietary fibre can be used in various functional foods like bakery, drinks, beverages and meat products. Influence of different processing treatments (like extrusion-cooking, canning, grinding, boiling, frying) alters the physico- chemical properties of dietary fibre and improves their functionality. Dietary fibre can be determined by different methods, mainly by: enzymic gravimetric and enzymic—chemical methods. This paper presents the recent developments in the extraction, applications and functions of dietary fibre in different food products.
Not that we should go around gnawing on wood like beavers, but maybe that’s why some indigestible foods seem like we should be able to eat it