Yes, Open Access is an ethical question, in part.
But there are other issues, some ethical and some political and institutional. Another ethical issue: if we make publishing easier, will people simplly publish more because they can? I am not raising this so much as an issue of publishing things that lack epistemic warrant (for instance, because of peer review — though I’m less convinced than others that peer review usefully serves that function). I’m raising this as an issue of whether we ought to publish more, just because we can? Or should we focus on publishing better work, instead?
Then there’s the policy angle: CU Boulder is following Harvard in linking journal subscription rates to FRPAA. If enough libraries do this, it will force publishers to adopt Gold OA. But is that better than Green OA? What’s the right balance between the two?
Finally, even if the technology allows for new publishing models, will disciplines adjust their standards for tenure and promotion to allow for publications in non-peer-reviewed journals? Or do we need a new model of peer review?