Actually, a couple of cases and interpretations/summaries I found indicated that a website may very well be considered "publishing, duplication, reproduction, and reissuing."
Moreover, the non-prohibition of "mere distribution or any other activity which does not involve hiring, contracting for managing, or otherwise arranging for the participation of the performers depicted" is interpreted to be a protection for the non-decisionmaking support crew (stage hands, gaffers, grips, messengers, mail room attendants), not those who make the editorial decisions of the material that finds its way into publication.
If the OurPPA.com were a revenue-producing device (like a men's magazine), then it might be worth the financial cost of gaining and maintaining model documentation and it might be worth the financial risk of legal defense if the Alabama or Georgia courts decided to go after the PPA (those are the states where website servers reside and where editorial judgments for the site are made, respectively...notice that those are quite conservative states).
If the PPA were the ACLU and thus had the primary mission of expanding the boundaries of freedom of speech, then daring Georgia and Alabama courts would fall into the mission of the organization.
But OurPPA.com is not revenue-producing, nor does the PPA have the primary mission of pushing the boundaries of freedom of speech. Having a vital interest in the protection of freedom of speech is not the same thing as having the mission of expanding the boundaries of freedom of speech--it's like the difference between a state militia and the Marine Corps.
PPA is certainly not obligated to bear that risk and cost for individual photographers who do intend to expand the boundaries of freedom of speech, especially given that those photographers have more ability to self-publish today (via the web) than in any time in the past.
PPA already annoys federal and state governments by combatting them on issues like copyright modifications and health insurance. PPA is already on their "we don't like these people much" lists...why create unnecessary vulnerability on an issue that is not of substantial benefit to the vast majority of PPA members?
Being a publication venue for frontal nudity is of too minimal benefit to the vast majority of the OurPPA.com audience to take on the cost and risk. It just isn't worth it.
As for us not actually "producing" the images, you are correct because distributing the images is not seen as breaking the law.
Article (2257) Paragraph (h) section (3)
the term “produces” means to produce, manufacture, or publish any book, magazine, periodical, film, video tape, computer generated image, digital image, or picture, or other similar matter and includes the duplication, reproduction, or reissuing of any such matter, but does not include mere distribution or any other activity which does not involve hiring, contracting for managing, or otherwise arranging for the participation of the performers depictedIn that matter then yes you are correct that we are not directly liable for the distribution.