His point, as far as I can tell, is that in different countries legally define rape in different ways, but that shouldn't change what we find morally wrong.
To extend on what I think he is saying, he thinks it should be possible to say a thing was morally wrong regardless of which country it happened in.
If we're discussing if we think a person did something morally wrong, I'd rather talk about why we think that rather than pointing out there is a law against it (especially when the laws are different in different places).
> “I think it is morally absurd to define “rape” in a way that depends on minor details such as which country it was in or whether the victim was 18 years old or 17.”
Is this really a topic that "requires the disinfecting power of sunshine"? Do we really think we've gotten the topic of statutory rape so wrong that we need to rethink it from first principles?