It is not because they are brown or "Latino" 

""To be admitted to the Visa Waiver Program, a country must meet various security and other requirements, such as enhanced law enforcement and security-related data sharing with the United States and timely reporting of both blank and issued lost and stolen passports. VWP members are also required to maintain high counterterrorism, law enforcement, border control, and document security standards.""

do you think maybe it is because nations south of our border have very lax standards when it comes to handing out Visas and Passports??? Could it be that there is a record of documents from some countries are easy to falsify?  Marticula Cards????

It is really good to get the whole story before posting it...Something "The Raw Story" has a problem with!