High-fructose corn syrup (HCFS) seems like an unlikely villain, since HCFS is 55% fructose, 45% glucose, whereas cane sugar is 50% fructose and 50% glucose (molecularly bound, but separated before it even hits your stomach), and fruit sugar is 100% fructose.
But fructans are NOT digested into fructose from what this article seems to say. Some polymers are easily digested (starch), others are not (chitin, the exoskeleton of lobsters; or cellulose, also known as insoluble plant fiber.)
Fructose is converted to glucose before it is utilized by your body. Therein lies the problem.
I'm not aware of any fruits containing only fructose. It looks to me like some fruits, like plums and bananas, have a slightly higher percentage of glucose than fructose.
I suggest understanding a word:
Oligosaccharide.
The author is an idiot and should not be writing about the gut.