Hating the right sells, so if someone does something unpopular, accuse him of being a conservative.
I wouldn't be surprised if the Liberal Party themselves promote the meme to try to win conservative votes away from the actual (socially) conservative parties. It sort of makes sense. The leaders of the Liberal Party are usually some combination of lawyer/dopey/religious but their policies are significantly less partisan.
Sure, right wing parties say they want to lower taxes (but rarely do so) and left wing parties say they want to increase them (and often do so) but we're talking more about brand marketing and appealing to voters than significant changes. Right wing parties tend to be more authoritarian on some themes (gay marriage, drugs). Left wing parties tend to be more authoritarian on other themes (hate speech, gun control, more regulations). No one in politics really care about individual freedom if not to please voters close to the elections.
We definitely should adopt a different system to categorise political parties - but to me the Australian Liberal Party looks liberal enough for today's world.