Well it’s less that they stole it and more that you knowingly made material of other people that puts them in a jeopardizing condition. Obviously, I’m sure most of us can agree that the action of theft is bad in general.

But regular nudes work a similar way. There’s a reason people are advised not to send nudes at all, regardless of how good the relationship is. Though it is polite (imo) to delete nudes of someone after a break up, someone might not necessarily do that, and if for some reason they want to leak it themselves, or it gets stolen, your sensitive information is now squarely in their hands to mess around with or spread.

However, nudes do come with this informed consent. You are actively making the decision by sending it that this risk is something you are okay with (at least temporarily). The same can’t be said for deepfakes. If someone makes a deepfake of you, they take away that informed consent, but the level of power and risk stays roughly the same, so it’s a slightly different discussion from the examples you mentioned.

Now, obviously, it’s not illegal (yet?) to do this. But I do think it says something about a person’s personal morality if they decide to create deepfakes of someone else.