I'm not naïve enough to think there hasn't been some nasty songs sung over the years on Celtic supporters buses, though I highly doubt you'd hear racist songs on them these days, but my point is the treasurer is saying their behaviour as totally unacceptable, but from that clip it looked like wasnt just one or two guys, a lot of the bus seemed to be singing it, and I didn't hear even one voice ask them to stop.
I reckon this would be a regular thing on that bus, and the only reason it's now being condemned by the treasurer is that their racist behaviour was caught on video.