The question reads:
I see an NDA as a pseudo-public document, something you need to read in detail before you acknowledge and opt-in to limit rights (discussion of topic/tech).
Unfortunately for this view, the law normally sees an NDA as a private contract, except when it is alleged that it violates public policy. If an NDA explicitly or implicitly includes itself in the list of things not to be disclosed, then posting it would be a violation of the contract. In such a case the party posting the agreement would be subject to whatever consequence the agreement specifies for violation, unless that person had a valid defense. The operator of a web site where the document might be posted would not normally ne a party to the agreement, and so would not be liable for hosting it, unless some other limitation applies, beyond the NDA itself.
An NDA can indeed be a significant limitation on the signer's freedom to discuss certain topics, and a person would be wise to consider it in detail, and perhaps consult a lawyer, before signing one. But that does not mean that the person should post or distribute it publicly, nor that the person is automatically entitled to consult NDAs that others have signed. There are sufficient sample NDA forms available that a person can compare an offered NDA with other possibilities, and get an idea if an offered NDA goes beyond the usual terms.