Why do they call people from New south wales cockroaches?

"One night in Sydney former Queensland coach Barry Muir sat down to watch the news on a dodgy TV. It was the mid-1970s and Muir had tuned in to catch a glimpse of a report on the New South Wales side."

http://www.abc.net.au/local/audio/2012/06/13/3524401.htm

Essentially the audio clip says that the players looked like cockroaches because of the antenna sitting on the telly which was appearing above their heads. He used it at training, and it snowballed from there.

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Old Answer which was listed....

i think it's because of a coachroach that is on the endanged species list that lives on lord howe island..