Please, please do not misunderstand me. What happened in Connecticut is an atrocity in my mind. Could it be avoided? Who really knows?
Just remember:
Source:
Wikipedia
October 6, 1976: Cubana Flight 455 - 73 killed
November 20, 1979: Grand Mosque Seizure - 127 killed (excluding perpetrators)
August 2, 1980 : Bologna bombing - 85 killed
April 18, 1983 : 1983 United States embassy bombing - 63 killed
United Airlines Flight 175 hits the South Tower of the former World Trade Center on September 11, 2001.
October 23, 1983: Beirut barracks bombing - 299 killed
March 8, 1985 : Beirut car bombing - 80 killed
May 14, 1985 : Anuradhapura massacre - 146 killed
June 23, 1985: Air India Flight 182 bombing over the Atlantic Ocean - 329 killed
December 21, 1988: Pan Am Flight 103 bombing over Scotland - 270 killed
March 12, 1993: Bombay bombings - 257 killed
April 19, 1995: Oklahoma City bombing in the United States - 168 killed
August 7, 1998: U.S. embassy bombings in Kenya and Tanzania - 224 killed
September 11, 2001: September 11 attacks in the United States - 2,998 killed
October 12, 2002: Bali bombing in Indonesia - 202 killed
March 2, 2004: Ashura massacre in Iraq - 170 killed
March 11, 2004: Madrid train bombings in Spain - 191 killed
September 4, 2004: Beslan school hostage crisis in Russia - 344 killed
February 28, 2005: Al Hillah bombing in Iraq - 127 killed
July 7, 2005: 7 July 2005 London bombings in the United Kingdom - 52 killed
July 11, 2006: Mumbai train bombings in India - 207 killed
March 27, 2007: Tal Afar bombings and massacre in Iraq - 152 killed
August 14, 2007: Yazidi communities bombings in Iraq - 796 killed
November 26–28, 2008: 2008 Mumbai attacks in India - 185 killed
July 22, 2011: 2011 Norway attacks - 77 killed
December 6, 2011: Ashura bombings in Afghanistan - 80 killed[11]
January 20, 2012: Nigeria attacks - 185 killed[12]
May 21, 2012: Sana'a bombing in Yemen - 101 killed[13]
June 13, 2012: June 2012 Iraq attacks - 93 killed[14]
July 23, 2012: July 2012 Iraq attacks - 116 killed[15]
The above is only a portion of Mass Murders in history's time. The article references many more. They are all tragedies.