They don't view themselves that way:
"The Internet Archive is not interested in offering access to Web sites or other Internet documents whose authors do not want their materials in the collection. To remove your site from the Wayback Machine, place a robots.txt xfile at the top level of your site (e.g. www.yourdomain.com/robots.txt) and then submit your site below." (link)
Expanding on that a little: placing a "robots.txt" file on the web site is effectively construed to mean that the site owner (and presumed copyright owner of the materials) is explicitly refusing permission for other entities to copy his material.
If Wayback refuses to comply with such requests, then they set themselves up for infringement lawsuit, even though in this case the material (supreme court cases) should be considered public domain.