When people read the title of the novel, they might see it under different perspectives.
Somebody could reject the book because they don't understand the meaning of the word Foe. So they might not want to read the book.
A second possibility could be that they could connect the title to Daniel DeFoe, the writer of the novel Robinson Crusoe, by assonance. So they might want to discover if there are some differences or same things between the two novels.
A third way might be that they find the title strange and so they are curious to understand why the writer gives this word as a title to the novel.