I suspect it means that all their mod staff probably work remotely and there was nobody in the office over the weekend for them to inform about what happened which is why it took until Monday for them to actually do anything. If they had even a single programmer in the office over the weekend they could have easily took everything down to prevent these things taking place...
That's what I was thinking. Even if one moderator was working over the weekend do they not have a supervisor they could have called or even emailed? There wasn't even a reply on facebook until monday. Is it possible literally no one works weekends?