You’re arguing that it’s not worth the effort to be clear over a single letter, from a place of what appears to be some American-oriented xenophobia. Not a good look.
But to your point about travel, that isn’t analogous. This isn’t an American tourist going to another country, where the temperature context is Celsius. This is an article disseminated globally; by its very nature, the context should be agnostic of locale, and so it would behoove the authors to be clear (again, with a single letter) so that there is no confusion.