If the thing that makes it interesting is that the solution is unknown to everyone, then would you also oppose humans publishing solutions? Once the solution is published the mystery is gone.

Also, just because someone else knows something shouldn't make you any less curious about it yourself. If you don't know it then you don't know it, regardless of whether somebody else does. https://www.lesswrong.com/posts/L22jhyY9ocXQNLqyE/science-as...