"Chemicals" as generally used in that sense has no meaning whatsoever except "this is bad because we say so" - it gets used for a huge variety of things, many of which are the exact same molecules that are found in fresh fruits and vegetables.

I think they're going for something more like what I would call "synthetic" or "processed" - "this is a thing the production of which involved large amounts of complex human intervention, usually involving non-biologically-mediated chemical reactions, after it was extracted from an animal, vegetable, or mineral source."

But in actual practice it mean "whatever we feel like scaring people about today."