Being a Canberra Raiders supporter, I certainly didn't pick them for colour of their jersey!
I actually started following Australian Rugby League as a kid, a few years before I even became a supporter of my Super League team.
I've seen my team win 1 Grand Final, so it certainly has nothing to do with glory.
And I've witnessed heaps of Australians down under wandering the streets in Man U, Liverpool, Chelsea, West Ham, blah blah blah jerseys. I guess it's just like EPL fans wearing Barca and Real shirts, it's not only obvious but fact that NRL is the better competition