This isn't the "official" answer, it's my best guess. But if you're dealing with nullable ints and comparing them, you most likely always want the comparison to return false if you're dealing with two "int?"s that are null. That way if it returns true, you can be sure you've actually compared two integers, not two null values. It just removes the need for a separate null check.
That said, it is potentially confusing if it's not the behaviour you expect!
