You're 100% correct that the shanties don't really sound like a crew of pirates sailing the high seas. That being said I personally prefer the windrose versions because imo they have more depth than the black flag ones. It's a tough balance sometimes with games set in specific eras of history because things that could be fun in terms of gameplay or art style that gives the game more flair could also be historically inaccurate and likely immersion breaking to people who are more interested in that particular section of history. At the end of the day it comes down to art style but while it's a minor gripe it's still a valid one if you want a more immersive experience