Why is it utterly stupid? He's generated some rapport with his captor/hijacker - something that combat after capture training tends to encourage (though to be fair posing for a selfie wasn't specifically in the lessons I had).
If it was real and the guy wanted to detonate it then they're a bit screwed anyway, being friendly isn't really an issue - if the 'bomber' was angry/tense etc.. he'd not have been able to approach him in the first place.
this..they had a good inkling he wasnt a suicide bomber by the fact that he hadnt blown the plane up when it was in the air..so the chances were good he wasnt intent on killing everyone
after that, we dont know what was actually said on the plane. the hijacker looks pretty calm and perhaps the passengers didnt feel threatened, or he had made assurances to them..we just dont know
maybe he had explained what he was doing and so they felt comfortable approaching him.
until we know all the facts its seems rash to condemn him
but he doesnt look worried in the photo so you can only assume they knew what was going on at that point


