While I can understand your sentiment, it might also well be possible that such a person might be convinced of the righteousness of their cause. The article even gives some quotes along those lines. To paraphrase: "it's better if someone like me does the interrogation than someone who does not care about the Geneva convention".

I think it is very hard to judge the motivations of people from the outside. The whole point of the article was to illustrate how torn you can be between your convictions, what you want to do, and what you actually do.

Most of us are very lucky insofar as we do not have to face such tough choices.