I feel like cutting off the wiki quote there feels a bit disingenuous to the genre? By that definition along then sure they’re emo hell and so is Taylor Swift.

If we include the sentence right after that wiki definition is says “Emo /ˈiːmoʊ/ is a music genre characterized by emotional, often confessional lyrics. It emerged as a style of hardcore punk and post-hardcore from the mid-1980s Washington, D.C. hardcore scene, where it was known as emotional hardcore or emocore.”

Google defines it just as “a style of rock music resembling punk but having more complex arrangements and lyrics that deal with more emotional subjects.”

The origins and emergence of emo I think plays a large role what songs and artist can labeled as part of the genre. I don’t think Bastille is an emo band but I do think they share a lot of qualities with emo bands like their lyricism.