I really don't understand how they can be fine with so much illegal content hosted on the site.
Ex: https://archive.org/details/JohnMayerMusic
This is being featured on the homepage! No way this is in the public domain.
Ex: https://archive.org/details/JohnMayerMusic
This is being featured on the homepage! No way this is in the public domain.
What are you referring to, that they will take things down only when a complaint is filed? That doesn't really speak to the quality of the archive that it's there in the first place.
More broadly, archive.org does operate in a legally gray area. But by trying to be a comprehensive archive but providing straightforward mechanisms for rights holders to opt out (including retroactively)--and by being a non-profit that doesn't run advertising--they seem to strike a reasonable balance for most people.
The quality of the archive? Not archiving something because of copyright is what negatively affects the quality of an archive.