Why do VISA and MASTERCARD continue to do business with countries like Nigeria and India?

Most online scammers with fake listings to steal money from people in Western countries are based in those countries, and yet companies like VISA and MASTERCARD continue to provide credit card services to those countries.

Banks in Western countries pay out hundreds of millions a year in refunds to people who have been scammed online by Nigerians and Indians, and they get away with it because credit card companies continue to provide service to them, and the banks in Western countries pay for the fraud and allow it to continue.

Why do Western financial service companies support and enable scammers in the third world and subsidise their crime and financial terrorism? It's truly bizarre in my opinion.