This strikes me as funny.
Isn’t this the same situation as vitamin supplements? They are all separated from their natural configurations in food, yet no one makes a big deal out of it.
I do think that fiber and vitamins and phytonutrients should be consumed in their whole food forms, but I also think that the FDA should be consistent.
At least we know what vitamins are! I had to look up xylooligosaccharides:
http://www.sciencedirect.com/science/article/pii/S2212619814000588
Wow! Looked at the article and xylooligosaccharides sound like the next miracle drug 
And money-maker in the processed food industry! 
I’m not cynical, am I? 
I wanted to share this article about eating foods as close to their natural states as possible, not refined:
https://thefastingmethod.com/fibre-reduces-insulin-how-to-lose-weight-x/
My interests are in the potential benefits of fiber on overall health; not so much interest in weight loss. Maybe the weight loss angle of the article help sell the program or catches the attention of readers? I wonder why the article seem to address mostly Type 2. Good food is good food,right? Eating foods closer to their natural states seems like a good idea whether one is a diabetic or not, whether type 1 or 2.
Digressing slightly: I am not keen on the idea of adding additives to a highly processed refined food. It reminds me of the time when a food chemist told me about olestra, a fat substitute . https://en.m.wikipedia.org/wiki/Olestra. Her description of the side effects, and that olestra would affect vitamin absorption…etc. described in the Wikipedia —> scary as heck to me😯.