Preventing the spread of pornographic deepfakes is simply an extension of very reasonable existing laws banning revenge porn..

Deepfakes in general should have significant legal regulation around them as an extension of libel/slander/defamation/disinformation laws. Imagine if you pissed the wrong person off, and they generated a bunch of deepfake videos of you cruelly killing dogs, then circulated them around to your friends, family, or potential employers. Or imagine if a politician campaigning for reform has a deepfake video generated where they argue in favor of pedophilia.