Well from their site
Moderation
Since there are no global admins, the administrative control of a subplebbit rests solely with its creator. No one else can moderate content or accounts unless the subplebbit creator grants them permission.
So, it's not that there's no moderation. It's just "subplebbit" creator/delegates controlled as there is no over arching site wide company able to moderate it on the whole.
It will mean, as a user, you'll have to be liberal with removing subplebbits from your own feed though. I'm sure there will be some.. not so pleasant subplebbits appearing.
Ultimately you get something interesting out of rofi by creating scripts that call it every time a user needs to select something. Your Reddit example would be trivial to do, at least core functionality wise, if not exact key presses.