Theres a song by country singer Alan Jackson. Its called 'When Somebody Loves You." Well that means country is emo. And theres a post grunge/alternative band, Silverchair. They have a song called 'Miss you love.' Damn theres that love emotion again. I guess they're emo too. And all those hardcore bands, with their angry lyrics. Guess what, anger is an emotion, so they're all emo as well.
Point is, every song has emotion in it, and emotion is not what solely defines an emo band.