I interpreted it to mean people feel as though they didn’t consent to having their information trained on, because for many folks, they published articles, open source projects, etc. assuming that they were only helping other people. It’s quite a shock to see megacorps use such data to create machines which threaten the livelihoods of the original authors themselves.

Also, much of the data used to train LLMs are not strictly public domain. For example, copyrighted books and source code with attribution-requiring licenses feature heavily in many corpuses. There are still pending lawsuits against the labs here, yet they continue to push forward. It’s no surprise that there is popular demand for redistribution.