No, there is no irony nor is it an oxymoron. “Great” primary definition refers to size and magnitude, as in “great wall”, “great war”, “great plague of Marseille” - and that is not an oxymoron by definition too. Webster dictionary even gives example of “great bloodshed”. And only a fourth definition by importance is “used as a generalized term of approval” as in “I had a great time”. So do not confuse the primary meaning with the usage more common for you personally. It was the Great War because it dwarved everything else in history by comparison.
1 Like