The internet is fairly new. As times change, there are new reasons to add laws. Revenge porn law is directly related to how easily this stuff can get disseminated to hundreds/thousands/millions of people. That wasn't possible to this extent or even close to it 20 years ago. California is just the first state to have one. If other states think it ends up working well in California, I'm sure it will be adopted by more of them.
And that is not at all what I meant by intent. I was talking about the intent of the law, not the intent of people posting videos of naked people. The intent of the law is to punish people who post porn videos of others in order to get revenge on them. IMO, the intent of the law was not to punish people for sending a video back to the person in said video. However if Washington thought it was sexual assault (I don't think he did), then the law should apply here too, imo. And there are cut and dried cases where you can prove guilt if you have access to comments made by the parties posting the videos.
If you think posting porn without the subjects' permission is a freedom of speech issue, I don't know that it's worth discussing with you anymore.