I wonder how much of it is really "concern for the children" type stuff vs not wanting to deal with fights on what should be allowed and how and to who right now. When film was new towns and states started to make censorship review boards. When mature content became viewable on the web battles (still ongoing) about how much you need to do to prevent minors from accessing it came up. Now useful AI generated content is the new thing and you can avoid this kind of distraction by going this route instead.

I'm not supporting it in any way, I think you should be able to generate and distribute any legal content with the tools, but just giving a possible motive for OpenAI being so conservative whenever it comes to ethics and what they are making.