The ACCM site [http://www.youngmedia.org.au/mediachildren/05_12_R18+_games.htm]: ACCM response: The link between the consumption of media violence and violent behaviour is twice as strong as the link between passive smoking and lung disease
Note "consumption of
media violence"; 'media', not just games. That includes literature, TV, TV news, TV current affairs, films, music (rap - we're looking at you here).
But having an 18+ category for films is somehow fine while games are 'worse' because they are 'immersive'. I think that the ACCM is deliberately ignoring the fact that a TV or film audience is also immersed in the medium,
and has to choose to passively stand by and allow violence to occur,
and empathise with characters and therefore suffer the violence or perform it by proxy,
and take pleasure in or condone the violence when it is done for the 'good cause' (e.g. torture on 24). The audience could - as my mother used to - turn the TV off when it got violent, and do soemthing constructive like gardening.
The self-righteous dogmatism of media like 60 Minutes teaches people - especially children - that it is good and proper to have a definite opinion on an issue, precluding individual thought, discussion, and investigation. The overbearing authoritative tone of the 'reporting' attempts to make people think that opinions presented to them are both true and fully justified, neatly turning viewers into unthinking consumers of TV commercials, and allowing the producers to support their own moral and political agendas with public 'opinion'.
In summary; allowing an 18-year-old to play Silent Hill is no worse for them than allowing them to watch any of the Rambo sequels or 60 Minutes report on the 'boat people problem'.