Watch out for literary critics. They can get feisty.
If there's anything Marxists hate more than Ronald Reagan, it's other Marxists. Marxism is notorious for in fighting. Okay, these are professors we're talking about, so the body count is pretty low. But still.
The biggest fight inside the Marxist ranks was one was between "Vulgar" Marxists and, well, everyone else. Basically, "Vulgar" Marxism says that literature is a direct reflection of society. If your economy is x, then your novels are y. Basically, the idea is that everything in the novel is totally determined by socioeconomic factors.
This "reflective" theory is pretty discredited by now. (Don't writers think for themselves just a little bit?)
There are two alternatives: "Ideology" versus "Cultural Materialism." Theorists like Terry Eagleton and Frederic Jameson argue that literature is a form of ideology. In other words, it's a way for the people in charge to spread their view of how the world works. For these theorists, even writers who aren't explicitly trying to justify an ideology are still probably doing it without knowing it, since their whole livelihood depends on keeping things the way they are.
For theorists like Raymond Williams and Alan Sinfield, on the other hand, literature is just a part of culture. Culture, for them, is not just about artists justifying the way things are. Instead, books, songs, and movies are complex; they say more than one thing—and often stir things up.