Should soldiers be subject to punishment via the Uniform Code of Military Justice?

Via the Uniform Code of Military Justice (UCMJ), the military can dole out discipline in the same ways as ordinary employers -- such as via loss of pay, suspension, firing, and so on. In addition, it can prosecute and punish behavior in military court leading to imprisonment. That's something a regular job could not do. Is that valid? Should soldiers have to function under a whole different legal system than civilians? Why shouldn't crimes by soldiers be prosecuted in ordinary courts?