Probably exactly what happened. He may not have been little Johnny Jihad, just some skull-full-of-mush moron from a hippy-dippy family who thought he could pull a Timothy Leary and "Turn on, tune in, drop out" from the Army and do a walkabout in Afghanistan. The Taliban probably couldn't believe their luck when they came upon him looking for some poppys, and grabbed the idiot. That's what I'm guessing, head full of whimsical theories put there by dad, sure he was going out to play Dances With Mullahs, and just had the longest wake-up call in history.