The only thing that should prevent this faction from becoming official is sanctions they've got. Just in my PoV.
About activity thing, this faction had 8 days of activity in all(3 columns). Even if these were generated just in events, which I believe Corsairs were included just in ONE, then having 8 days of activity generated by raids and whatsoever speak for itself. Just to compare some of the latest new OFs have barely 3 days in quarter, while this one had 8 days in one month.