There is not much discussion.
He and his brother left NZ as teenagers wanting to be elite world distance runners. They went to Kenya to live and train then ended up in various parts of the country/training camps as well as being separated when one of them ended up in Ethiopia.
While there I am sure they were exposed to all the sh-t we know happens in Kenya with respect to doping. Easy access to pharmaceuticals, little to no out of competition doping control and seeing how easy it was to get away with.
At this point what do you have to lose? Really? Roll the dice like the masses of Kenyans do. There is basically no incentive to not cheat - you get caught and so what, you aren't in NZ where even if you were nobody cares because you aren't an All Black rugby star. Load your refrigerator up with WEPOX 4000 and you are off to the races. Literally.
This is such a simple situation to understand and not surprising in the least. Always wondered if he (they) could get away with it and finish his (their) career without getting popped but they almost all get a little too greedy or invariably slip. It's about that simple really.