In a former life, I taught probability and stats at the Air Force Academy and then used that knowledge to do test and eval and space systems. This looks like a perfect area to apply some more rigorous statistical analysis. With that said, I don't think it takes any serious stats skills to say that this sport can be "site" specific. The real question is what makes a specific site better than another? Thus, breaking down the data by country doesn't do the analysis any justice. You would have to look at all sorts of crazy data to see if this is truly site specific or if it is boat specific, driver specific, weather specific (temp, winds, etc), time of year specific, country specific or a multitude of any other factors.
It's an important question to answer if you are a world record holder but that's about it.
The most important thing is that everybody competes at the same site in a tournament. Golf is a perfect example. All the different courses are rated by slope and difficulty to make sure the handicap system works for people playing any course, but people also understand that some courses play hard or play easy. Relative performance is the only thing that determines a winner on any given day.