I reckon its a cultural thing, we grew up with those two very much loved manufacturer's & name plates, they were like family.
They are atm two longtime Bathurst competitors that made winning race drivers household names, our nation is very sporty & that synergy is what makes us love our Falcons & Commodore's plus the fact that both the cars were manufactured here in Australia.
All those factors i mentioned imo is why certain Commodore drivers around here anyway like to pose/showoff when I'm out & about lol.
Its perhaps a sign of respect & a celebration of our car culture imo - now with Holdens current woes in shifting vehicles because it seems they took for granted their old customer base. There i said it lol!!
I believe that cultural synergy is what they lost & maybe why their (Insignia cough cough) Commodore is tanking atm.
Anyway, so now when i see a Commodore driver pose off in front of me its actually a tip of the cultural hat & a show of love & joy for their favourite cars.
And no its not the "ive got a bigger you know what" type of thing lol!!
cheers, Maka