There were individual authors in the class. They initiated it. Individual authors were allowed to sign up.

If you’re so interested, go read past the headline. Maybe you’ll find that you’re working about what “authors” will agree to.

To sign up for what? The experience of approximately every author on the planet is that they found out that Anthropic did something bad at the same time they were "opted into" the class. The only thing they could do is opt out and litigate on their own against a company with a valuation approaching $1T.

This is a sweet deal for lawyers and for publishers, and nothing else.