Half of a Yellow Sun: 1st impression; Ugwu; the individual vs isms

Reading Chimamanda Ngozi Adichie’s Half of a Yellow Sun. Shall I continue? Perhaps I should, perhaps I will change my mind. My impression at the moment is that the book has the precise problem that worried me when I picked it up—that an author who seems obsessed with gender and/or race (in this case, and) will likely risk letting her social agenda take over and undermine her own literary work. Not only so—what do I see when I read reviews or critiques of Adichie’s works? Nigeria. History. War. Women, men. Feminism. Africans. Race. Igbo. Why do people not speak of literary merit when praising a literary work? 
Take the character Ugwu. Ugwu comes to work for Professor Odenigbo as a houseboy. At the start of the novel, he is 13, uneducated, having finished only 2nd grade, and simple—he on the 1st day keeps some chicken meat in pockets, intending to give his family when someone visits; irons socks; thinks that only evil spirits have grass-coloured eyes; curses that people get diarrhoea; thinks that killing a gecko gives you a stomachache; thinks stew with arigbe (a kind of herb) could soften Master’s heart, etc. In short, he’s a simple, superstitious, ignorant boy. The 1st chapter, though told in the 3rd person, focuses on his point of view.
Now take these lines: 

“Ugwu did not understand most of the sentences in the books, but he made a show of reading them. Nor did he entirely understand the conversations of Master and his friends but listened anyway and heard that the world had to do more about the black people killed in Sharpeville, that the spy plane shot down on Russia served the Americans right, that De Gaulle was being clumsy in Algeria, that the United Nations would never get rid of Tshombe in Katanga…” 

Do you think such a boy would pick up such information? I don’t think so. Adichie wants the information in there, because she wants the readers to know what the professor and his friends talk about, but it’s Ugwu’s point of view in this passage and it’s a weak device. 
But not only so. As I read Half of a Yellow Sun, it doesn’t feel like the political bits are there for world-building and characterisation, but on the contrary, the characters, their thoughts, their conversations… are to serve the author’s ideas. It makes me think of Vasily Grossman, who is praised for his focus on and love for the individual—the individual is, to him and to many great Russian writers such as Tolstoy* and Chekhov and Nabokov, more important than any kind of isms; whereas for Chimamanda Ngozi Adichie, I’m afraid that the issues of race and gender are more important. 
If that’s the case, that would be bad for her as a novelist.



*: Of course, you would argue that Tolstoy isn't a pure artist like Chekhov and Flaubert, who care for no ideologies. Tolstoy seeks to teach. But at his best, the artist triumphs over the preacher, and nobody can create characters as real, complex, self-contradictory and full of life as Tolstoy does.