The banking concept of education is like a narration, the teacher is the narrator and the student is the listener. According to Freire the teacher is the subject while the student is the object. This teacher-student relationship has to be considered to be oppressive for the following reasons: the teacher teaches the students are taught, the teacher knows everything the students know nothing, the teacher thinks and the students are thought about, the teacher talks and the students listen-meekly, the teacher chooses the program content, and the students (who were not consulted) adapt to it. All these things make up the banking concept of education which resembles oppressive characteristics. The banking concept of education does not liberate instead it oppresses students. This type of education where the students are treated as objects and made to store as much information as possible allows ignorance and submission to occur because there is a power imbalance where the teacher has the power and the students are powerless.
The banking system of education is not oppressive in its current use. One may argue that having different levels of education is a tool of oppression, but the banking system itself does not oppress. First, the term "opression" is defined in webster's dictionary as "unjust or cruel exercise of authority or power". If this is true, then the banking system cannot be oppressive since there is no real oppressor, that is, a group of people excercising power over another, because all of mankind uses it at least to some extent. The banking system is just another observable aspect of the way the world operates. For instance, if a tree fell onto a man's car preventing him from going to work, that tree would not be an oppressor, rather an aspect of the world we could only observe. However, the way we handle what we observe can be oppressive. An example of this would be having a law that made it illegal to park a car under a tree. With this in mind, the banking system is not oppressive, but the way we react to it as users can be.
"You previously said, "the banking system cannot be oppressive since there is no real oppressor, that is, a group of people exercising power over another"" in the banking concept of education there is clearly a person(s) who have power over others. The teachers have complete control over everything concerning the classroom. They choose the material that is taught and the students must learn it. They perceive that the students know nothing and they know everything. Freire says "narration (with the teacher as narrator) leads the students to memorize mechanically the narrated content. Worse yet, it turns them into "containers", into "receptacles" to be "filled" by the teacher." Students are therefore degraded to less than human while the teachers are elevated to positions of power because students regard them as essential to their education. In the banking concept of education students are not truly learning what they are doing is storing information. Since students do not possess the knowledge to change their environment they must adapt to the reality created for them by the oppressors. For the student to not be oppressed they have to be given power through knowledge which the banking concept of education does not provide.
The banking concept of education is based on the acquirement of large amounts of information. According to Hirsh it is favorable to know large quantities of information in order for society to understand each other. Freire says "Education becomes an act of depositing, in which the students are the depositories and the teacher is the depositor. Instead of communicating, the teacher issues communiques and makes deposits which the students patiently receive, memorize, and repeat." In this type of education students are not expanding their knowledge; they are simply memorizing information which they do not truly understand. According to Freire "Knowledge emerges only through invention and re-invention, through the restless, impatient, continuing, hopeful inquiry men pursue in the world, with the world, and with each other." What this means is that knowledge comes from asking question and discussing the issue at hand which are not characteristics of the banking concept of education, instead it fills the students with information that the teacher sees as important. The result from a lack of knowledge is the absence of transforming power. In the banking concept of education the teacher(s) has all the power and the students which are reduced to objects have none therefore the banking concept of education is oppressive.
I will first respond to your second round claims. It is true that all teachers do percieve themselves to know more than their pupils in the subject they are trying to teach. Similarly, the teacher's teacher considers himself more knowledgeable at the time he gives his lesson. The point is that no one person, even the "teacher", can know everything, even in a banking system of memorization. Based on this fact, the teacher would be oppressing while being oppressed, and this does not make any sense. To prove that the banking system of education is not oppressive, we can look at its earliest form - language. The general concept behind language is that there are memorized vocal patterns that create words, which we give meaning to. If language was based upon Freire's "education through liberation" concept, there would be no patterns to study - everyone would scream and yell at each other without much being accomplished. At this point, the oppression of being unable to communicate for the creation of technology (food distribution, transportation, entertainment) would surpass the alleged oppression of the system itself. Furthermore, the banking system is based on the principle that there are things in the world that do not change regardless of our views. To ignore this principle would be absurd. Lastly, the banking system of education works in a way that can only oppress those who refuse to use it. By deciding not to acquire the information from the banking system, you agree to suffer the consequences of not having the necessary tools to surive, similar to the social contract theory of John Locke and others.