If you go up to someone in the street, and tell them about the plastic in the water supply and food they eat, how it's harming them, and that we need to better clean it up and regulate it, they're going to understand exactly what you're talking about, and they won't get into a debate with you about whether you're talking about dead skin, artificial skin, or BPA.

They won't understand, they'll just think they do. Just as if you talked about the dangers of "chemicals" and how dihydrogen monoxide kills thousands of people a year.

I've seen countless disagreements on numerous topics caused by people thinking they both have the same definition of a term and even more instances of confusion because the intuitive implicit definition that came from the example usages they'd seen of a term was a non-representative subset of the things matched by the explicit definition.

Nuance and clarity of language matters, otherwise you'll ban "chemicals" and discover you actually have no sane definition of it and are inflicting a lot of unnecessary suffering.