Having your sub be unmoderated is against reddit TOS, whereas taking a sub private is not yet against the official TOS.
Process and technicalities like this matter a lot and can effect a platforms actions.
But if neither make headway, just going unmoderated is the logical next step. Yeah, reddit could take over moderating the subreddits. They can also do that if they're set private. But they don't want to. They outsourced that to volunteer moderators so they could get free labor. If they want to run their own moderation, and submit their own content, the reddit corporation can have fun with that.