Discussing individual chemicals by name is inefficient, confusing and almost certainly requires scientific citations to be remotely worthy of discussion.

Going by groups of chemicals is a bit better, but then citations are largely not applicable.

There are no synonyms or near synonyms. The dictionary definition of ”chemical” (noun), however, is explicitly clear:

1 : a substance obtained by a chemical process or producing a chemical effect

2 : a drug

I posit that the person saying ”chemical” is not being lazy, they are being scientifically accurate while enabling rational discussion.

It’s anyone saying ”but EVERYTHING is chemicals” that needs to check the dictionary.