…the Greens do not want computer games that have high levels of violent content, sexual objectification of women and drug references available to people under 18 and they support regulation that would achieve this.

Unfortunately the reality is that computer games with high levels of violence, sexual objectification of women and drug references (or in many cases all of these things together!) are already available to people under 18 in stores at this very minute. As the article points out nicely, keeping games with this sort of material out of the hands of people under 18 would be far easier with an R18+ rating than without.

Source: WA Greens confirm opposition to R18+ game classification (Michael Meloni, Somebody Think Of The Children)