I know, and that is why it needs to be separate. Otherwise it essentially becomes the DH EU timeline. Where almost every story was its own little pocket timeline of people knowing/not knowing about the Aliens, or where earth had been invaded or hadn't been invaded by the Aliens. That was annoying, but it didn't matter because those stories didn't effect what was happening in the movies.
When you start doing that in actual film, that influences other film, that gets a little harder to try and rectify.