"The type of enemy we're dealing with would be torturing and killing our captured troops even if we kept our own prisoners in five-star hotels."

The governments in the region don't even apply Geneva type rules in regard to it's citizens. The terrorists say they love death more than the West loves life. They think they are bragging- they think this is "good".
Now, the region [or Islam] has certain customs they might follow [but this unrelated to Geneva], but again the govts don't necessarily follow these things and it's a certainty that the "holy ones" who go to porn shows, before committing suicide mass murder, aren't going to follow these customs- if they aren't in the mood or it doesn't serve some Propaganda end.