And you assume that everyone in One Piece just cares so much to keep up with the current times? I don't have time to worry about the rest of the World because I am working, and have a family to feed. Not everyone is glued to the news 24/7.
So my point is, is even in this day and age when information is available at the click of a button, it's still hard to keep up with everything when you have real shit to worry about.
But yeah, let's pretend everyone in One Piece should know everything because they have telephones, and receive Government propagated information via newspapers.