Piracy isn’t a libre licence.

Libre licence means sharing the source code and the game assets.

Here piracy means free to play.

And you’re right free software doesn’t mean the author doesn’t get paid. But that’s not the point here.

Lastly, in some legislations (author’s right), a statement like this one don’t work because the author himself cannot violate his own rights. Which mean that people can be sue for pirating a work even if the author stated that people can pirate it. To me, it’s endangering the audience.

On the bright side, it’s still nice to have an author acknowledging piracy doesn’t steal sells and that culture is meant to be shared.