Yeah I came across the full song on twitter, Cohen knows how to build it up over its eight minutes! What's skilfully done is that for the certain lyrics even the music gets racist to cue the audience!
From the footage it doesn't seem there is a big crowd of people joining in like with the raucous reaction of 'Throw the Jew down the well.' Another video shows the police arrive. Perhaps the attendees weren't happy because they worked out they were being pranked, but a woman can be heard which suggest she wasn't happy with the offensive lyrics 'it's not okay is it'. 'It's inspiring hate and violence.'