>Interesting. So under this working theory, the entirety of the IA is fundamentally against copyright unless specifically allowed/released per site?

IANAL, but basically yes. It's one reason why the IA respects robots.txt even retroactively. The reality is that, if something was posted publicly by a copyright holder and intended to be shared, the overwhelming majority of people/entities don't care that it's being archived somewhere but there's no particular exemption for something like the IA.