In my view this is much ado about nothing. Who knows why certain songs get taken up by certain sets of supporters but they do. For instance why on earth did Scottish football fans take to singing "Doe A Deer" from the Sound Of Music?? I don't know - but they did. There's no logic other than songs get taken up by sections of folk then become more widely popular. We do in Scotland have real problems with objectionable sectarian songs being sung by Old Firm fans in particular but Swing Low is surely being sung with innocent intentions. Just communal singing. There is actual racism to deal with in British sport, with abuse being shouted at black players etc, but this song is maybe a diversion from dealing with real issues?? The most objectionable thing with this one might be it is just a wee bit boring. They only sing the chorus - over and over and over and over again! I too remember after rugby drinking here in the Scottish Borders in the late 70s and this was sung as a drinking song with all the lewd gestures etc - but it seems to have since become associated specifically with English rugby fans I imagine simply because they took to singing the chorus over and over at games.