I'd go further.
It's really easy to think the meaning of "dihydrogen monoxide" is obvious if you already know how to parse terms written in that language. But it's far from obvious.
To understand what "dihydrogen monoxide" means, you have to know that "di" means "two", and that "oxide" refers to oxygen. You also have to realise that "mon" in this context means "one" - note that it's not "mono", because if it was "mono" then it would be "mono-xide". Actually, it's harder than that, because you need to know how you should break down the words into their components - e.g. that "dihydrogen" should be broken down into "di"-"hydrogen" but not "dihy"-"drogen".
If you haven't learnt the language used to spell out chemical formula you don't have a way to understand the details. I'm sure there's plenty of smart, well educated people who don't have this specific knowledge yet know full well that water is two hydrogen atoms and one oxygen atom.
This issue is more a matter of knowledge than intelligence.