Sadly we have many hobbyist who do great work, but they are completely naive about the world. I'd hate to see the work go to waste. I think archiving these things are important, sadly people who work like this are making a ton of assumptions about how the world works and often completely ignore legal issues. It's often good that they do, if someone sat down and tried to handle the legality of the project first, then it would never get off the ground.
Right now there's some hope that some Swedish organisation, The Internet Archive, maybe even YouTube, can step in and save the work. Then again there's a risk that no one can help.
It is not much different that people building a community on Facebook, because it's easy, it gives them a ready made platform. An easy to use platform. Then they're surprised when Facebook close their account for violating a policy that was always there, but they never actually read Facebooks terms and condition (which I can understand).
I'm sorry it happened to the guy, but you're right: "What did you think would happen?" The only surprise is that it didn't happen earlier.