Reflections on Fort Hood shooting

I saw news reports saying that the gunman was heard calling "Allah Akbar" as he rampaged through Fort Hood. There were also reports of him donning traditional Muslim garb and becoming extremely religious after the death of his parents.
What I find incredulous is that people are trying to figure out the motive for the gunman's rampage.
The use of language to filter ideas has already come into play as the man is now being described as a "rogue gunman" rather than a fanatical Muslim. His reluctance to do military service in a Muslim country is being downplayed whilst harassment of his religion is mentioned as a possible cause for his behavior.

What I think is that we should reflect on a lesson from history.
The Romans suffered their greatest defeat in Germany when their German commander Arminius aka Hermann turned against them and organized a series of ambushes with the surrounding German tribes. Hermann was a German who was trained by the Romans and fought for the Romans until they entered Germany. There he turned on his masters and used what they had taught him against them.
The mistake of trust was a very costly and humiliating defeat to the Romans. Have we learn't anything from this? Do we understand the nature of allegiance and loyalty or are we still making the same mistakes over and over again?