The strange thing here seems to be R’s use of ”list” as a name for a map-like key-value structure. The word ”list” is commonly understood to refer to a data structure which needs to be linearly (linked list) or partially (skiplist) iterated through to access a value at a particular index.
Sql has “tuples” for the rows of a result-set which are neither tuples nor lists in the “general sense” and are of a “record” type - names with values.
So what is a list? Depends on the context.
My impression is that JavaScript is another language like R that values flexibility a lot.
And yeah, I agree that R is rather casual about lists vs maps. It doesn't really care that maps are a great data structure in their own right. It just wants to slap names on list elements when it's convenient to access elements of the list by name.