Compounds really are not elements.
Of course compounds are made up of elements.
The synergistic effects can be deadlier or safer than indvidual elements – the point is that you can’t look at explosive sodium and gas-mask-requiring chlorine gas and decide that sodium chloride is a white powder that explodes in water and gives off poisonous fumes but conversely, you can’t look at carbon and note that it’s generally safe and look at how safe oxygen is if you’re careful not to set it alight and then come to the conclusion that carbon monoxide is safe.
Compounds need to be judged as compounds and not as elements. Doing otherwise is a basic mistake that undermines anything else you have to say about chemistry.