Nicknames and male banter are interesting in this context.
Lads often call each other names that relate to some aspect of their looks, personality etc. That's usually accepted amongst a group of friends or peers. Those same words can be used to insult and discriminate as well, indeed the names and how they are used often reflect some kind of power play in a social situation.
Even when used in a supposedly non-aggressive way names do reflect something about society. For example, I would lay big money on the chances of a black or asian man in a group of predominately white English 25 plus years ago having a nickname directly related to his colour/ethnicity. He could be the shortest, tallest, largest, slimest, strongest, have glasses, big feet or no hair. His nick name would still be derived from colour and/or ethnicity.
What's more his "mates" would be saying to him "no offence mate, but you are ....(black/asian)".
When I think of Aussie culture I also think of a certain cultures in Britain - some the same in lots of ways, some the sames in attitude. On the one had you can consider it to be basically just fun however the root of much of that culture goes back to a time when there was little social mixing of classes and races. It's easy not to take offence at a name when the person calling you it has the same colour and social standing - when it's your direct peers.
I think it is easy for white, middle class people like myself to suggest that those from the so called ethnic minorities chill out a bit and stop taking everything quite so seriously. It is especially easy when you, your parents, their parents - generations of your family - have not had to face decades of discrimination, abuse and lack of opportunity at the hands of another race.
There are clearly times when the use of someones colour or race is not racist and has no negative undertones however this does not mean that we don't need to demonstrate some sensitivity and respect for others.