Swing low sweet chariot...am I in the 19th century South?

Rugby fans and onlookers crowded the square and such today, seeing the parade and big to do here in town. I can't say I joined them 1) because I haven't felt good today 2) I'm not a rugby fan 3) I'm not British and 4) I didn't feel like being in a crowd. It still makes me wonder how on earth they got it into their heads to use the song "Swing Low Sweet Chariot" as a victory song. It's a song from during the time of slavery in the U.S., something the then African-American slaves would sing about dying and going to heaven. Somehow, I'm not quite getting the connection with a British sport. Maybe it's just me.