It isn’t “American indoctrination,” the ideas held by people are largely determined by their social relations and material conditions. Understanding how people come to their conclusions and the beliefs they hold is a fundamental aspect of theory, because it illuminates how we can change those beliefs.
Liberals generally want the same things Leftists do, but don’t understand the systems around them, their trajectories, or their weaknesses, and thus not how to overcome them or what needs to be done.
I think everyone that can read needs this message too. There’s a difference between knowing misogyny is bad, for instance, and knowing how and why it works and how to eliminate it forever.