Before going to film school, I thought that sci-fi movies were sci-fi movies. When I went to film school, I discovered that sci-fi movies were not sci-fi movies. Now that I have graduated from film school, it turns out that sci-fi movies are sci-fi movies.
If you've been assigned this book for a class, don't worry, the professor doesn't understand a word of it either. It's really easy to BS if you just skim it and memorize the rhetoric. And if you're really stuck, just say, "Genre films reflect and represent society's collective fears and desires" and you'll probably pass the class with a 'C'
Take it from me, don't take any film classes. Godspeed.