When I was in my early 20s and I'd had a massive night out, I'd jokingly tell people I'd been as "drunk as 10 Abos" and more often than not get a horrified laugh.

I had several Aboriginal mates and girlfriends in my teens, but even that intimacy hadn't opened my eyes to the fact what I was saying might be incredibly offensive and hurtful.

I'm pretty sure, aged 20, I would have argued that "Abo" was merely an abbreviation of the word "Aboriginal", similar to the term "Lebbo" and, like "Yank" or "Pom", just a harmless nickname.

I'd probably also have argued no one would be offended if I said I was "drunk as 10 Irish" or "Russians", so what's the big deal saying it about indigenous Australians?

The truth sank in about 15 years ago, when I realised I didn't get to choose what the word "Abo" meant and, however I intended its use, for many Aborigines it was a searing pejorative, loaded with cultural contempt.

So I stopped saying it because I respect indigenous people enormously and have since established and run a mentoring program for Aboriginal and Torres Strait Islander students wishing to work in the media.

(I also now use the expression "drunk as 10 homeless men" which, I guess, is insensitive to homeless men.)

I mention this because many Australians recently watched rugby league's first State of Origin match, played at Etihad Stadium, and the result was largely decided by a controversial try awarded to one of our pre-eminent indigenous athletes, Greg Inglis.

I know I'm not the only person to have watched his 100-plus kilogram frame slice elegantly through defenders at warp speed and mutter, awed,  "No way I'd tackle him."

I also know I wasn't the only person in the country to sit in a room last month and hear people scream "smash the Abo" as Inglis ran the ball (and if you doubt this still happens, I suggest you watch the next Anthony Mundine fight at a pub).

Tellingly, there wasn't an Aboriginal person in the room with the 15 friends I watched Origin with, but, equally tellingly, no one raised an objection; in fact, many laughed.

Everyone was drinking, we were having fun, and I guarantee those who shouted the epithets were saying it for shock value, not out of hatred for Inglis or Aborigines.

But still, there it was for us to reject and no one did. If we had, I'd wager someone would have called us "politically correct".

The next morning, I thought about why I'd stayed silent and realised I didn't want to shame a friend, to project superiority on an issue on which I've been less than circumspect myself.

I reflected, however, that, if someone had said something about Jews or Asians - not an uncommon occurrence in my suburb, either - I probably would have objected because I have close friends from both minorities.

I don't have close friends who are Aboriginal, just acquaintances, nor do I have friends who are disabled or morbidly obese.

Thus, when people voice slurs about "spastics", "retards" or "fatties", I have no familiar face to conjure on which to transpose the pain of the insult.

That's when I realised "political correctness" is not about controlling people's freedom of expression; it's simply about not hurting others - or their friends and relatives.

Yes, it's 2012 and I've just worked this out, but at least it's given me my response next time someone uses any of those terms in my presence.

"Fair dinkum, it's 2012, what year are you in?" I'll say.

I hope.

Sam de Brito's latest novel Hello Darkness is in bookstores now. You can follow him on Twitter here. His email address is here.