You didn't, of course, but playing devil's advocate and abusing terminology in the usual way, you have to understand a monad a little bit to know what to make of the type signature.
In practice I expect the comment you replied to is hyperbole and/or confused.
Haskell is an abnormality. Even in FP land.
There is likely no other language where you need to "understand monads" to understand `Hello World!`. Such "crazy stuff" has nothing to do with FP!