The "intention" word bothers me. Based on what most people are saying, if I am walking down the street and my camera falls out of my backpack and takes a fantastic picture, I am not the owner of that picture and I can't sell it. It is automatically in the public domain. The was no intent. There was no artistic input.
Based on you response, If I try to take a picture of a very quick event and I accidentally miss the event but get a good picture anyway, the picture is in the public domain. The picture was an accident and not the result of my creative input. If that is the case then there are a whole lot of copyrighted pictures that should be in the public domain.
I have read Mein Kampf and I don't see any problems reading works by historical leaders. Yes, the guy was a wacko that had almost no redeeming values but you can learn a lot from reading his works. The more you know about this kind of person, the easier it is to fight them.