While there are of course
legitimate academic reasons to study the text and regular folks may just be plain curious about the book, reading Mein Kampf isn't exactly the sort of thing people will want to do on the commute to work - which could be exactly why it's proving so popular in ebook format.
There is probably always a role for
academic libraries to play in the surrounding community, whether large or small, but there are also
legitimate reasons for
academic libraries to restrict public access.