:::::Yes, he also wrote: "Their story may be implausible, but it isn’t impossible."  And, indeed, that's true, but he wrote that before one failed the lie detector test, and the other remained silent. 
 :::::I suppose it's still technically possible that three radical Islamists just happened to be in Afghanistan during the period when radical Islamists were being called to war, but that they declined, or as you say, perhaps they were forced to go along with it even though it was somehow against their radical Islamist principles.  Still possible, but getting more and more unlikely. 
 :::::Somebody should have asked about the so-called "abuse" they'd received at GTMO while they had him on the lie detector.  That still seems to be taken at face value. 
 :::::