It’s all about definitions and it’s only misleading if you don’t label the graphs correctly.

In the old days I used to ensure that the monthly press release clearly made reference to ‘european carriers’ rather than just ‘europe’. I didn’t read the linked article too closely but I think I saw some vague references along similar lines.

Remember (once again) that IATA is a trade association and the purposes of press releases is to highlight the results of the membership rather than being a rigorous statistical data collection.