The man fulfilled his obligation. Officers are required to resign their commission even after fulfilling their obligation if they want to be certain of not being called up. I think calling the man names is without basis.
After I did 8 years of active duty, I got an unqualified resignation so that I would not get called back. Unfortunately, there are a different set of rules for physicians who can be called up at any time, with or without a draft and with or without physical problems that would preclude service for the general population. For example, I was classified 4-F after taking an induction physical because of a severe motion limitation of my right arm following an accident in college. However after graduation from medical school, the problem was not a barrier to my enlistment.