No, it's not those other things, that's just using the tool incorrectly. A NULL is definitely "we dont know", not false, not N/A, especially not any known value.
Yes and I think that Clojure handles nil pretty well, and it's a functional programming language like SQL. It's also interesting to see that Typescript has added an unknown type. So something that's a value in SQL (null being unknown) is a type in TS.