My question too, what do they expect him to hold, a feather duster?
Well, I went back and re-read the article and now I understand. The school has a Zero Tolerance policy against weapons, and who's to say that some enraged student wouldn't grab the rifle right off the photo and commence firing. Or that the thing might go off by itself. Or, maybe the Marine in the photo might have a touch of combat fatigue and just cut loose on the student body himself. I think the school administration acted prudently in banning this photo. You can never be too careful these days.