Terrorism: "the unlawful use of violence and intimidation, especially against civilians, in the pursuit of political aims." ~ Google
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No Lars, none of the people I listed were "terrorist acts", 2 however, were terrorists by definition. Notice an exception isn't given for "mental health" status or race.
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Dylann Roof meets the criteria provided by this definition. Mr. Roof admitted that he "did his part" for attempting to incite a race war.
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Christian's crimes appear to be racially motivated yes but also meet the criteria above since the motivation behind his attacks and the message he was trying to send is heavily politicized.
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Lanza's motivation may or may not meet the definition above but I have to ask you, how are the crimes these three have done any better than what people that fit your very narrow definition of terrorism done? How are the crimes that Roof or Lanza committed any less heinous than what Omar Mateen did in Orlando.