This is a bit naive and childish:

"how terribly shocking...I suggest also blocking China, 'cause they're commies, and France because they eat frogs"

The OP is not discriminating against Africa because of government systems, skin color, or diet.  He is trying to reduce lost revenue, credit card refunds and time due to fraudulent orders that almost all originate from the African continent.  The reality is that Nigeria is the 419 internet scam capital of the world, and the Nigerian scammers sometimes work from other African nations or even the UK.  If someone in Africa really, really must have something that Matt sells then they should pay with Western Union or international money order instead of a credit card.