This is naive. I don't necessarily know that the content is illegal until I've started playing it. By that point I may have already shared it.
Same issue with any p2p, I guess. You could start downloading a file with a harmless name and later discover it was a fake name.
I don't think that's naive, considering that after reporting adult sites with obvious CP, the sites are still up after several years.
Jurisdictions vary in how the justice system treats intent. You do not want to rely on lack of intent to get off the hook.
No, the people who run Peertube misunderstand how to communicate. This comes up every time Peertube is discussed. People think Peertube is a replacement for YouTube and that they can upload their videos to peertube.com or something similar. Then they learn, that, no, it’s just the software to let you run your own YouTube-like site. Then they have questions like the one above and get replies telling them they don’t understand. Maybe Peertube should just find a better way to communicate what they offer?
I believe you misunderstand the technology.
There are two components of Peertube.
The server you either self-host or you use someone else's. If you are hosting a server and you host other people's content, you register for liability protection under section 230 of the Communications Decency Act and section 512 of the Digital Millenium Copyright Act.
The client is where the "peer" in peertube comes in. If you want to be safe from liability, don't watch illegal/immoral content. You will be fine.