why does the military have their own court
Military justice The United States Constitution authorized the creation of a system of military justice. Article I, Section 8 permits the U.S. Congress to "make rules for the government and regulation of the land and naval forces."[26] Congress issued these rules first in 1806 as the Articles of War. Military justice during the American Civil War was governed by the 1863 Lieber Code. The Articles of War were superseded in 1951 by the Uniform Code of Military Justice (UCMJ).
Superior court In a number of jurisdictions in the United States, the Superior Court is a state trial court of general jurisdiction with power to hear and decide any civil or criminal action which is not specially designated to be heard in some other courts. California, Connecticut, Washington, Maine, the District of Columbia, and Georgia are all examples of such jurisdictions. In other states, equivalent courts are also known as courts of common pleas (Pennsylvania, Ohio, and others), circuit courts (Illinois, Michigan, Oregon and others), district courts (Louisiana, Texas, Hawaii and others) or, in the case of New York, supreme courts.