I agree that all military personnel must complete a battery of psychological testings even lie detectors. Many will say that they will not have a difficulty carrying out their tasks , but feelings and attitudes may change at anytime afterwards.
If this Psychiatrist had a problem with the US army killing Muslims overseas, he did not appear to have any difficulties dispensing those bullets to his fellow US army servicemen and women.
The other area of concern to me is this man's personal mental health.
As a mental health worker myself, I am fully aware and sensitive to the trauma that is exerted on the carer just seein and hearing of the tragedy of our clients/ patients.
A mind is a terrible thing to waste but is very easy for thoughts to highjack the mind beyond reality.
Peace and healing to the wounded, and the bereaved. The family of the psychiatist as well have my prayers.