Exactly. Last weekend I watched UFO conspiracy videos all day, just for the entertainment value. I see people reading Marx and sometimes even Hitler's stuff, and they're neither Commies nor Nazis obviously.
I wonder what people would think if I sat next to them on an airplane reading Mein Kampf, actually. Marx is academic-trendy enough that people won't look down on you for reading him, but Hitler's a different story.
I would think that anyone reading Mein Kampf is an avid student of history, maybe WWII history in particular. It seems much more likely than them being a Nazi.
Maybe. I don't know about the US, but in Europe, reading this book in public would provoke a strong reaction in people. (I think selling or even owning the book is illegal in several countries.) So I think somebody doing that would be more likely to be making a statement of some sort. What kind of statement, may vary... (They could have Nazi sympathies, or be vehemently anti-censorship, or just like to shock people, etc.)