Not a 'Tragedy'- Why Words Matter

When horrible things happen to people, one word is regularly used by news-gatherers to describe the unfolding events: 'Tragedy'. The Orlando massacre or the murder of Jo Cox MP were 'tragedies', apparently, according to some newspapers and the BBC news. Sorry, No, they weren't, and we shouldn't say they were. Now, this might be caused by sloppy English teaching when these news-people were wending their ways through school, but they (and we) shouldn't use that word to describe those events. Why?