I think people are looking too deep into this Map thing. He crossed the Country off the map because it's the Country he wants to destroy. Just like he put X's all over certain peoples bounty pictures. He just knows where the island is, and destroyed it. It's not some mystical map voodoo.
On a side note, it looks like "The Great Cleansing" has begun, and the targets seemed to be those that the Revolutionaries liberated, and switched sides. Countries are probably going to start back peddling, and allying with the WG again.