How can I justify why this work is titled The Lonely Londoners?

The novel The Lonely Londoners is a story written by Samuel Selvon about a man who helps his new country men arrive in London, get jobs, and find suitable housing.  The author calls this novel The Lonely Londoners because of the hatred, bigotry and mistreatment of the West Indians during this era.  There is even a quote from the book where one person says, "Why can't you be blue, or red, or yellow?  Anything but black." This is the type of isolation these people had to deal with during this period in London. The new people felt alone, afraid, and unwanted.