Caste system in equal society?

I’m on chapter ten of Brave New World. In creating a new world of technology and control, the world has become an unfeeling, cold, mass-producing monster. Things are being mass produced left and right, to the point in which PEOPLE are being mass produced. Lower caste people are purposefully being retarded in the embryo, just because of the caste. Technology has created the caste system, as well as perfected it. It seems to me that the government is attempting to make a society in which there is a universal equality among its citizens. The government, however, has instituted a caste system which separates people into groups in which some are superior to others. Control and mass production seem to be the most important things in the society. And one of the most important things to the people is soma, created by the government to help keep out any type of negative thought toward the Controllers. The caste system seems to be a key element to control. Why does Huxley feel the necessity to create a caste system within this world?