It's a problem that derives from the complexity of copyright law. The result is that the only way to be certain renders user-generated content sites completely

It's a problem that derives from the complexity of copyright law. The result is that the only way to be certain renders user-generated content sites completely unworkable. If your intent is to have a chilling effect on free speech on the internet, requiring a huge and messy legal process to publish something is a good way to do it.