That's not what that article says. The article is saying that it's chic these days to pretend that whenever evil is committed it is by people without a thought process - that evil is directly equal to insanity. Hence, "senseless." But it isn't. As the article points out, both the holocaust and the Benghazi embassy attack were perpetrated by thinking, reasoning people who had their own motivations and knew the difference between right and wrong. We vehemently oppose their motivations, but they had them, and thus, were not "senseless."
When you start categorizing all your enemies as insane (or "senesless"), it's a cop out. It means you've stuck a label on them that says "we can't possibly figure out what is going through these people's heads, so let's not even try." There are cases where that's true - the connecticut school shooting was senseless. However, Nazi Germany was not senseless. And those who cannot (or are unwilling to) figure out the motivations and thought processes of their enemies are at a distinct disadvantage to them.