I fail to understand why General Michael Thomas Flynn has not been recalled to active duty and

[madville]

48. And people don't realize how convoluted the military retiree/reserve system is

There are many different "statuses" one can be in after being on active duty. It also depends if one retired with 20 years of service or is past 30, there can be a window from 20-30 years as a retiree where one is still at a higher level of reserve status. I think there has been like one case of a retiree being recalled to be tried under the military justice system for a crime post-retirement because they were still technically in the reserves because they hadn't hit 30 years total time in service yet.