I think someone's aiming for the "illegal" angle, which they haven't said one way or the other (as far as I know).
In strict language, you are very right that it doesn't matter.
Oh, no. Someone was going for the Ageist angle.
Because the little snookums is a dewy 18, see. How is that relevant.
You clowns really gotta be more selective in your Reactionaryism.
Misterrob didn't say it didn't matter. In fact, he thought it was the most important fact of the story to comment on.
So, I'd guess it did matter to him.