Does that mean each player has to own the game, and if so, in what universe is DRM FREE not false advertisement?

this happens with every game released these days not only with wingspan. If the single player can be played offline then the game is drm free. Now don't get me wrong it would be great if developers released their games with LAN like terraria, and stardew valley did but they don't care since 99.5% of the people don't care if their games can be played offline.