I know why civilians control the military. But I think you have wrong idea about it. Politicians control top generals, but they do not control details of every military operation, and neither do you - so knowing the details of the specific operational planning of the army would not be very useful to you, unless you want you politician to intervene in specific operation planning - which would not be very good, as neither you nor your politician have the relevant knowledge. There can be situations where common knowledge is enough - e.g. if certain commander plans to kill all civilians in the city, you don't have to be in the military to know it's wrong and such commander should be removed - but such cases are very rare. Usually mass-casualty tragedies result from a set of very complex circumstances and varied set of coincidences and mistakes, and I'm not sure your politician will be qualified to figure it out.