Dictionary, any substance used in or resulting from a reaction involving changes to atoms or molecules, esp one derived artificially for practical use .
So technically you would be correct. It is formed naturally then separated by other means. The base is still created by a natural process as opposed to being say combined in a test tube. In a common sense usage I would not consider it to be on the same level as say cyanide or Ammonia. I would think most people associate chemicals with harmful substances. Vegetable glycerine, unless you are allergic to the source plant, is basically harmless. It is not a bi-product so much but an adative to moisturizes, soaps, beauty products, food etc.
I would.think this would be a preferable option to the previously mentioned MG Chemicals 408A or something else of that sort.
Glycerine is not formed naturally. It is made by a chemical reaction called saponification that also makes soap. It's also a waste product in the making of bio-diesel and it can be made completely synthetically from propylene.
However it is made, it is exactly the same substance whether from animal or vegetable sources.
The idea that chemistry only covers harmful substances is laughable.