Ah yes, I was not expecting players to have updated their 2.0 installs to 2.1, but yes, they are marked as Recommended, which means any mods not on 2.1 don't get auto-downloaded on new installs, but I suppose that means they might get auto-enabled if you are upgrading from 2.0 (and the 2.0 versions of those mods were already installed)
Maraxsis, Pelagos, and Planteraris: Arig should be the only Recommended planet mods that aren't on 2.1 yet (I think most of the Optional planet mods also haven't yet been updated)
EDIT: One step closer, Maraxsis is now on 2.1 (though tbh, I think most planet mods are still a little bit unstable with regards to 2.1; some runtime changes making things not work properly, even if they don't prevent the game from loading outright)