Serious answer: it was judged that the act of scanning and delivering the book was ‘copying’ it - which copyright laws say they need permission to do. The whole ‘we only let one person at a time read it’ thing was deemed to be irrelevant.

Note that I’m not commenting on whether a reasonable person would also interpret copyright law this way, or on whether the laws are fair, just what the judgment was.

Because publishers are assholes.

Are all "rich monopolists" the same?

Because they didn’t pay publishers for separate “ebook” licenses.

Because the justice and political systems, particularly in regards to copyright, are deeply corrupt.

Because billion-dollar capitalist rent-seeking bullies got their panties in a wad and threatened to bankrupt them with legal fees that the bullies wouldn’t even feel if they lost. And the archive is just a non-profit that were offering a not-for-profit service for the betterment of society, with literally zero actual negative consequences.

Trying to normalize a DRM system is not advancing the betterment of society. If IA wanted to be pro-social scofflaws, they should have published DRM-free epubs/PDFs/etc for download, copyright law be damned. If they wanted to be law-abiding, they should have declined to offer this service, and informed users of the existence of shadow libraries.