Like, banana-flavoured milk product vs banana yogurt - seed oil and potato starch compound with artificial flavorings vs REAL milk yoghurt with REAL banana.
It tastes different, it has different nutritional value and overall "chemical" product feels scammy because it tries to mimic proper one.
This is all about words, like, why do we use "Artificial" in Artificial Intelligence?
Chemical is just a bad word choice. Artificial, or ultra processed get closer to the issue. They still are vague with a lot of grey area. If you cook at home, you're also highly processing your food. The fruit in winter is likely also artificial, in some sense: Grown against the will of god/nature with pesticides, in a tent, in a climate that doesn't naturally feature them, devoid of flavour because they were artificially bred for yield, color and size, etc.
This is arbitrary subjective qualifier, goes somewhere between "isoamyl acetate" flavoring chemical and organic wild forest bananas. I would subjectively say that any grown bananas is REAL while isoamyl acetate made by rectification of amyl acetate is not REAL banana.
Maybe people are simply reacting to chemical-sounding words.