How can we analyse the social world? What tools do we have at our disposal?
Most social science has a set of tools derived from the natural sciences. They strive for something approaching a law-based description of social reality, in the way that physics (for example) tries to formulate laws (or regularities in the world), which then become part of theories. The goal of science is to create theories, which are explanations for observed phenomena, along with the ability to predict and control the phenomena.
Of course, social science has a much harder time than natural science in doing this. The social world is a messy place. There are few laws. But there are regularities, and there is structure. If there wasn't none of us could cope in society.
Critical theory resists these scientific ways of explaining the social world (although, importantly, it does not reject science as such, only the logic of positivist science). These have included the quantification of that world in terms of causes and effects, the controlled experimentation on that world, and the production of abstract models.
This type of analysis has often been regarded as ideology. What is ideology? Simply a theoretical construct that has no basis in the life-world. But isn't empirical social science rooted in the real world? Critical theorists would say no. It abstracts from the real world. It is not a world that takes free will into account. It does not take meaning into account. It treats us the way economists have always imagined us, as rational agents making decisions based on opportunities and constraints.