..oxygen molecules refer to oxygen and ozone and probably other oxygen allotropes, yes we all agree on that. ..
We do? It doesn't sound like it to me but if you are right then presumably the sticking point is the gas part. So we can all agree that the statement that all oxygen molecules are composed of two atoms is wrong? Whereas adding the gas specification apparently makes it correct: all oxygen gas
molecules are composed of two atoms.
To get back to your second reply where you state:i think for a very broad and literal interpretation, oxygen gas can refer to any gas that composes entirely of oxygen atoms.
but we chemists prefer to keep things simple. we dont use a term to refer to everything, when it is already ingrained in the common public.
Would this mean the statement in question would be regarded as incorrect if made very generally to a broad public?
In reply to your second point, don't chemists use the term salt to refer to every ionic compound composed of an equal negative and positive charged ions, and isn't salt ingrained in the common public to mean only sodium chloride? Is this the exception of chemists complicating things? I think just the opposite applies. That in science ordinary words which are used, are defined much more rigourously and statements of fact are always taken very literally!
Anyway thanks a lot for your input. Now lets see if others agree with you!