It finally dawned on me what hurts so much about that picture; it's a warning light, intended to help aircraft avoid collision with these tall structures. 

I hope we do not let this horrific tragedy make us cynical in all our human activities.  I hope we can maintain the optimism which makes America one of the most desirable places on earth to live.  We cannot predict every monstrous plan, nor forsee every potential for evil.  We cannot create lives of utter invulnerability in America without losing a great deal of what makes those lives so very much worth living.