I'm not going to speculate on whether Jamaican athletes are doping or not (my personal view is that there must be a culture of doping given the number of Jamaican athletes caught recently over the years). However, I want to point out that the numbers on Letsrun's quote of the day are misleading and deliberately inflammatory.
"The Jamaica Anti-Doping Commission performed a mere 106 anti-doping tests in all of 2012 ... Compare the Jamaican number - 106 - to the number of tests performed by the U.S. Anti-Doping Agency in 2012: 4,051. Or the Russian National Anti-Doping Organization: 15,854. The Chinese: 10,066. German: 8,077. Italian: 6,794. British: 5,971. Australian: 5,186. Japanese: 4,956. Indian: 4,051."
Two reasons:
1. Quoting these figures without mentioning relative size of countries is quite misleading.
US population: 314 million. Anti-doping tests/million people: 12.9
China population: 1,344 million. Anti-doping tests/million people: 7.5
India population: 1,241 Anti-doping tests/million people:5.5
Jamaica population: 2.7. Anti-doping tests/million people: 39
Per million people, Jamaica tests >3x more than USA, >5x more than China. That said, it's fair that it should be higher. Given Jamaica's outsized impact on world sprinting, my guess is that a higher fraction of the population play pro sports in Jamaica than elsewhere (atletics, certainly!) - but I don't have figures to support that guess.
2. Anti-doping is expensive, and Jamaica is a poor country - it doesn't have the resources of USA or China to pour into anti-doping.