I meant it isn't "worth it" for Jason Furman to mention it, because he can assume that virtually everyone listening (or, at least, his intended audience) not on

I meant it isn't "worth it" for Jason Furman to mention it, because he can assume that virtually everyone listening (or, at least, his intended audience) not only assumes it as a given, but has it so ingrained into how they think about the world that mentioning it in the first place would actually be weird. To borrow your example, if a fish started every argument with "we are surrounded by water, therefore..." I don't disagree with you.