Napoleon adhered to the Enlightenment principle known as equality. Napoleonic Code guaranteed equality of all citizens before the law.
The author's purpose for including this paragraph is to explain the resistance that Branch Rickey willingly took on in an effort to being the process of ending segregation in Major League Baseball. This paragraph serves to explain that there were people off the field who also helped revolutionize the game.
If you are referring to concrete and abstract nouns, then "North America" would be considered a concrete noun, as one can physically touch the earth in Canada and say, "I am touching North America". If it were an abstract noun, such as fear, one would be unable to physically interact with it, as one cannot physically touch an emotion or idea.
Although there are many themes of "The Landlady" by author Roald Dahl, one of the main themes is appearance vs reality. The Landlady is very nice and generous towards Billy which causes him to ignore the sinister plot the Landlady is conjuring.