I think there's a big disconnect between 'western' and traditional Buddhism on this topic. We are nowadays very acclimatized to what has happened since the 1960's but there have been massive changes in social attitudes towards all these questions as a result of 'the sexual revolution' - more than many people realize.
I think traditional Buddhist teachers would regard pornography as transgressive of the 3rd precept (grossly so, in fact). Whereas most 'moderns' regard 'consent' as the criteria for what is, or is not, ethically or morally acceptable. So the criterion has changed from a generally prohibitive view to a more individualistic and, it has to be said, hedonistic attitude in Western culture. It is very much a matter of 'each to his/her own' and 'whatever appeals to you' - but it so easily becomes, as the OP has noted, a slippery slope.
I notice on secular forums, that if you take express a negative attitude towards online porn, you are tend to be categorized as 'repressive' or 'authoritarian'. The hostility towards what is regarded as 'censorship' is especially pronounced amongst the kinds of 'liberated' folks you would associate with interest in Eastern spirituality. After all, Buddhism became really established in the 60's and the 60's generation were at the vanguard of the sexual revolution. It seems to me that as a result a lot of Western Buddhism has a very liberal attitude towards sexuality which is not actually representative of the original tradition. I think a lot of traditionalist Buddhists are rather shy and reticent about the whole question, which can easily be interpreted as agreement or acquisence. But my honest view is that internet pornography exploits
civil freedoms for selfish and commercial reasons. It completely severs the link between sexuality and loving intimacy, which, I would hope, is the demarcation between wholesome and unwholesome sexual relations.
Case in point: there is an old magazine article on Buddhanet on the topic of Buddhist sexual ethics
, in which the author says he visited:
the website of Salon Kitty, ...which describes itself as 'one of the world's leading BDSM houses.' BDSM stands for bondage, discipline and sado-masochism. On Salon Kitty's main menu is a statement of ethics, which the duty of care and overall responsibility ' the dominant' owes 'the submissive,' not least around the obviously crucial issue of consent. In part the statement of ethics says: Implied in consent is the responsibility of the dominant partner in any BDSM scene to monitor the wellbeing of the submissive to ensure that the submissive is stable and that the consent is still operative.
A description follows of the mechanism for instantly withdrawing consent - the uttering of a pre-agreed 'safe word' - which immediately brings the procedure in question to an end.
Then the statement of ethics resumes: In order to enjoy the possibilities that the world of BDSM offers, one must first discover respect and trust both of oneself and of others. Elements of all five precepts are there, including the last. On the basis of this statement we can conclude that Salon Kitty comes closer to Dhamma than fundamentalist, social engineering killjoys of various religious persuasions!
I must say, when I read this statement, I found it very disturbing, although not really surprising.
It also notes:
Publication or use of pornography which eroticises women's subordination thus plainly contravenes the third precept. But by no mean all pornography does so, and other sexually explicit material might be equally innocent.
I also recoil from the notion of 'innocent pornography'.
The article has link to 'a rejoinder' at the top which does advocate a more traditionalist understanding. But recall all the many verses in the literature about 'the canker of sensuality'. Whereas it seems to me that a lot of what is going on in Western society actually panders to sensuality. I think if anyone wants to pursue them then it is their perogative in a free society. But I think rationalising it so that it appears to be 'wholesome' or 'innocent' is deeply mistaken. Spirituality involves sacrifice, it often involves *not* getting what you actually want, but undertaking what needs to be done, and quite often they conflict, sad though this might seem. The easy way, instant gratification, anything goes, attitude of the modern world deeply undermines that, and it is a hard fact to acknowledge.
Disclaimer: in saying this, I acknowledge that it is a personal issue and a source of inner conflict.
He that knows it, knows it not.