I've not bothered to read the code but I see no mention of a distinction between a country's intrinsic ping times and that limited by physical distance.

c in vacuo is an unbeatable constant and it slows in a dielectric. That's to say that not only do the distances from NY to the pinged sites have to be taken into account but also so do the velocity factor(s) of the cables not to mention delays in switching and regeneration equipment on the way. All these unavoidable, physically inviolable, times have to be factored out before we can get an accurate picture of a country's or region's actual performance.

I'd reckon to get an accurate picture of ping timings would be rather complex, as one cannot simply draw great circle lines on a world globe to get distances to destinations as one would also have to take into account the actual paths taken by submarine cables etc.