A - Because if they were the "Young Black Octobrists" singing "Kill the Boer" in the capital, as part of a worldwide solidarity event, nobody would have said a word. But because it was a group of young Christians, singing the national anthem in its entirety everybody loses their $#@! and runs them off.
B - Because it was a skirmish in the Marxist revolution. Nothing could be "newsworthy".
Nobody thought of doing a medley because almost nobody, including myself, find anything wrong with the line.
Only by using the most tortured of logic, can that line be spun into anything even remotely "racist".