"To produce agave syrup from the Agave americana and A. tequilana plants, the leaves are cut off the plant after it has aged seven to fourteen years. The juice is then extracted from the core of the agave, called the piña.[2] The juice is filtered, then heated to break the complex components (the polysaccharides) into simple sugars.[Need to cite reference for production process] The main polysaccharide is called inulin or fructosan and is mostly fructose. This filtered juice is then concentrated to a syrupy liquid, slightly thinner than honey. Its color varies from light- to dark-amber, depending on the degree of processing."
So we have juice extraction, heating to break up the components, filtering and concentrating. It just shows how far the industry has gone to consider that as natural.
Or alternatively :
"An alternative method used to process the agave juice without heat is described in a United States patent for a process that uses enzymes derived from the mold Aspergillus niger to convert the inulin-rich extract into fructose.[6] Aspergillus niger, a fungus commonly used in industrial fermentations,[7] is "generally recognized as safe" (GRAS) by the U.S. Food and Drug Administration.[8]"
We have a process to alter its chemical structure, luckily it is "generally recognized as safe".
Just because someone says it is natural doesn't mean that it is. Natural to me is picking an apple off a tree and eating it. Some food does need processing. Meat and some veg needs cooking, but anything beyond that is processed in my book.
Thinking that good and bad is as easy as natural and artificial is exactly the type of bad simplification that end up teaching people that GMOs are unhealthy and meat is bad for you. Nutrition is complicated, and if you want to understand it there's no substitute for the research.
Let's also be clear - no one in this article is a nutrition expert.