I thought that copyrights apply only to financial or business use of copyrighted material and that they are freely available for non-profit hobby or educational use. Also, how does Warners view buying and selling of old Fawcett comics? Are they now going to demand a share of a seller's profit from a comic book?
It all comes down to fair use.
Under certain circumstances, material can be quoted verbatim for purposes such as criticism, news reporting, teaching, and research, without the need for permission from or payment to the copyright holder. Even an school will still need to abide by copyright laws, a book can be photocopied fine as long as they don't exceed 10% of the book. A school might still have to hold a copyright license to allow this (depends on country law)
As for a hobby, as an artist you could make fan art of your favorite character fine but if you tried to sell this fan art on a t-shirt / poster you could end up in hot water if it still closely resembles the original character.
Disturbing a movie / comic etc as a hobby is still copyright infringement even if you don't make a profit. Under copyright law, it is illegal to download or share copyrighted materials such as music, comics or movies without the permission of the copyright owner. If this wasn't the case, file sharing music, movies, comics and games wouldn't be an issue and wouldn't be taken down. This defense has been used previously when the P2P programs were first under threat and the courts sided on the copyright holders.
As for selling / buying a physical comic book or a movie etc, once a copyright holder sells the copyrighted volume to a consumer, the copyright holder’s rights have been exhausted, and the consumer has the right to dispose of (not copy, but dispose of) the book any way he or she sees fit. If this didn't exist there would be no second hand market and this is why companies these days are pushing to digital versions of movies, books, games, comics because they retain the rights and you are restricted from selling the items so killing the second hand market. Most digital items these days are protected with Digital Rights Management (DRM) software.
PS. I'm not a lawyer so take all of the above with a pinch of salt and always do your own research