So? It's pretty clear that the owner knowingly allowed it and perhaps even promoted it. It's obvious that this person broke a serious law. Should the FBI just turn a blind eye because shutting down a hosting service won't be 100% effective at eliminating that content forever? No. We don't prosecute any crime conditionally on the basis of how effective that specific prosecution is at eliminating current/future instances of the same crime. Just because prosecutions of some Internet-related crimes are unjust doesn't mean you should employ mental gymnastics to side with every alleged Internet criminal.