This was not "some sort of valid complaint", it all happened under the cameras and TPTB were witness to it all. They should have stepped up. The message that should have been sent (and not only to women) is "this behavior is not appropriate, we don't want it in our show and we are putting a stop to it now".
As Kellee said, if Dan had behaved appropriately, none of this would have happened. The pressure to think before acting should be on the man in this situation, not on the woman.
If an assaulter suffers consequences for their actions it's not the victim's fault, and it's not up to the victim to decide what they want the consequences to be. There are rules and laws, and if Survivor producers don't have rules about this type of assault and are OK to let it happen on their show, I'm not sure I want to watch that show any more.
Disclaimer : I'm not from the US, so not sure of how things work out there, but in my country (France) a magistrate can initiate an investigation when they have knowledge of the occurence of a crime even if the victim does not want to press charges. Just recently an actress has spoken up about being assaulted by a movie director when she was a teenager, and even though she says she would not press charges, the French justice system has opened an official investigation.