This was the last word from the creator re: copyright stuff.
tl;dr your stuff is yours to do whatever with but the actual language of the copyright info on the site itself is very outdated because CYS was a project he made in college 20 years ago.
The main function of it as it exists, as least as I've understood it is that if someone loses access to their work after they get banned for being a child groomer (completely random example! Haha. Hah...) they have no legal footing to cry about that.