Question: Does Rush Limbaugh enter into legal agreements claiming to be another person?
Question: Does Rush Limbaugh admit that his parodies are parodies; instead of presenting them to be true and factual accounts?
Question: Does Rush Limbaugh create pornographic material and claim that those he is against were involved therein?
Your analogy fails.
Only in your mind. Again, fraud isn't was is belong alleged here - "cyberbullying" and stalking is. If it's fraudulent, the charge them with fraud. It isn't fraudulent because there alleged perpetrators have not enriched themselves or benefited in any way. A basic understanding of criminal law, might be helpful here.
Perhaps Facebook could file a civil suit for fraudulent infringement, but that would be ENTIRELY up to Facebook. It would not be a criminal allegation, but a civil allegation.