”Idiomatic” - is a ridiculous tautology I wish people discussing languages would stop using.
The only non-idiomatic code written seriosly is that which the compiler/interpreter does not understand.
Claiming universal superiority of style is shallow and thoughtless.
Intentional obfuscation is a different thing.
When computer people name things, it is with a tenuous grasp of meaning of the words they are using. You kinda have to roll with it.
If you are really enthusiastic you can write _obsfuscated_ C. And people can kind of agree what that is when they see it.
But _idiomatic_ ? Good luck defining what that is.
The term has sort of stuck in Python and there it's purpose is a bit more clear. There is this _object_ way of doing things, there is this _expression_ way of doing things etc and the interaction patterns work really nicely.
But you can't really use that expression in other languages which lack the same level of institutional design without sounding very much out of touch.