The things selected for inclusion on a Google Maps tab are an editorial choice. I'm suggesting they are analogous to a "recommended book list" -- a subset of all the available books that a librarian has chosen to highlight. Just as being listed in Google's index is analogous to being shelved in the library. (Surely, no one here is suggesting that anything be removed from Google's index.)
Otherwise - Yes, Mein Kampf is available to everyone who can use internet / library / ...