That's sort of like asking if Tim Berners-Lee has worked out the criminal content on the World Wide Web?
PeerTube isn't a centralised service, it's a piece of software that anyone can use to set up their own service.
Content on the internet is the responsibility of the person who hosts it and/or uploads it. It's nothing to do with the software that the server runs on.
If you see something illegal, report it to the authorities and they'll arrest the person hosting/uploading it.