I Am Surprised

@geoam1 Porn; the depiction of erotic behavior in pictures or words intended to cause sexual excitement

It was likely a lot of other people reported it too. Why the admins didn't just mark it adult themselves I don't know, perhaps this poster did this a lot and their final warning was ignored.

But that report button is there for a reason, and you did the right thing reporting it, and it got rid of someone that was likely trouble, although nothing will prevent them coming back under a new name.