If adults want to watch other adults engaging in consensual sex acts they are entitled to do so, we are told.
Savvy producers of heterosexual pornography are also quick to point to a small but growing body of porn that is marketed to couples, or women, in an attempt to persuade us that their industry is "fun", "sexy" and "harmless". Porn, we are told, has gone mainstream.
What is missing from recent public debate, however, is an analysis of the themes that thread through much of today's most sought-after porn.
It is widely accepted that porn is marketed and produced primarily for men, and is about how men - not women - want sex.
Women are commonly portrayed as existing for male sexual pleasure, willing recipients of whatever men love to do to them.
Dr Robert Jensen, an author and respected journalism professor at the University of Texas, has traced growing trends in adult porn. He warns that the content of pornography is "increasingly cruel, degrading and hostile to women".
The appeal to men, he observes, "is the sexualization of male dominance and female subordination".
(Warning: the following material contains graphic detail that might be disturbing to some readers.)
Jensen has researched the content of contemporary mass-marketed pornography in the United States for some years. His initial review of "typical" videos rented by the "typical" customer, provided to him by his local video store, revealed common threads.
Jensen found that many sex scenes involved one woman with groups of men.
Double or triple penetration of the woman was another common feature.
Invariably the woman was subjected to verbal abuse, which Jensen observed progressed through the videos in its "ugliness".
Video covers themselves were misogynistic.
Why is it that porn-using men are turned on by young women being referred to as little bitches or sluts?
Put to one side the argument that pornography is freedom of speech. What does pornography say about its mainly male audience? About men? About masculinity?
Jensen makes a basic and provocative observation: "Masculinity in this culture is in trouble".
Themes of woman-hating and subtle (and sometimes not-so-subtle) violence that saturates most of these "mainstream' videos" are lost to most men whose use of porn comes in short bursts, says Jensen.
This is because most men view porn as a masturbation facilitator, with viewing often ending once ejaculation has been achieved.
Jensen believes pornographers need men to identify with the men in the videos, not to have empathy for the women. He notes that pornography requires that men repress empathy, yet "empathy is part of what makes us human".
Once men ask: "Do women really want to be penetrated by two men at the same time?" the pornographic game is over. Pornography can work only if women remain "less than human".
Pornography is big business. In the United States some 13,000 new porn videos are produced each year, with more than 700 million videos and DVDs rented annually. Last year alone, American consumers, mostly male, spent an estimated US$12 billion ($18.4 billion) on adult porn, an industry that nets around US$60 billion globally.
This does not, of course, include the massive global consumption of free porn of any genre that is accessed online.
Jensen notes that just as we have come to see that racism is a problem of white people, sexual domination is a problem of men.
As a society we need a shift, locally and globally, in the collective male consciousness about sexual dominance. Men need to unpack attitudes, beliefs and behaviours that perpetuate the sexual denigration of women.
If pornography teaches us anything, it is the need to reconsider masculinity, and what it means to be a man.
* Denise Ritchie is a barrister and founder of Stop Demand Foundation, a non-profit organisation that calls for local and global action to stop sexual violence, against children in particular.