However, the legal environment is very different than in the commercial world or consumer piracy, as it generally involves various legal exemptions (differing between locales) that do allow such usage. For example, I work in NLP research on aspects that involve handling large corpora of copyrighted text. It's easier to do it with cooperation of the publishers for various practical reasons, however, we still can and do use also the works of the publishers who would refuse to grant any permission, because local copyright law has specific exceptions that allows the usage these works for noncommercial research purposes. Doing so is not ignoring their rights, their rights are not violated but rather they are limited; their exclusivity right (privilege would be a more appropriate word) to make copies is not absolute. There are even some countries with explicit legal duty for the publishers to provide digital versions of their works to national corpora where they will be used for (among other things) machine learning models.
The specific consequence, however, is that we can't legally share the full datasets which we are using with the public, like it was done in the original post with this particular dataset, as that would be a violation of the publishers' commercial rights; we can provide them to specific researchers for limited noncommercial purposes only. But I can download this dataset or one like this and use it my research legally; just as I can rip up a physical book, scan it, make a digital copy and OCR it, and use it in a research corpus (with copies distributed to other researchers) even if the publisher disapproves.
Or is the trained model a derived work of those books?
Training a language model, I would argue, is equivalent (in terms of being derivative) to generating a list of the top ten words in a corpus of text. Not really a derived work.
Edit: https://the-eye.eu/public/Books/humble_books_20180509/
Cue the "they're depriving me of my income" complaints from authors.
That was not the question.
Perhaps we should figure that before we start a dystopian nightmare of written material.
The GP is objecting to the casualness with which privacy rights and intellectual property rights are ignored by so many in the AI community, not to a choice of whether they object to one or another specific manifestation of how the community is doing so.
[edit added]: Those who would argue "no, there is no casual ignoring of rights", consider for example the official DMCA takedown instructions for the collection [0].
[0] http://the-eye.eu/dmca.mp4