There is no gray area here. Medical professionals are bound by an oath to "do no harm." When they devise ways to rape prisoners via "rectal hydration", when they supervise torture to make sure that it does not result in death or a prisoner who is too permanently impaired to serve as CIA witness or operative, when they interrogate prisoners under guise of providing mental health services,
they have done harm. Massive harm. They have done harm using the skills they were taught during their medical training.
If a doctor or nurse or psychologist decides that he or she can best serve the country by participating in torture, then that med professional must be willing to give up his license to practice on anyone else. Ever. Because who among us would trust a doctor or nurse or therapist who knowingly tortured?
Each state has a medical board to keep us safe from quacks, hacks and criminal doctors. We have a board to make sure that the ICU nurse taking care of Grandma does not have a drug problem. Our therapists are licensed, and we demand that our states make sure that they follow certain ethical guidelines. If a psychologist uses info she has obtained in sessions in order to get close to a client and start a sexual relationship, she loses her license. Shouldn't a psychologist who uses info obtained in sessions in order to devise better ways to torture a prisoner get the same treatment?
This is not merely a matter of punishing the guilty.
Our government has been entrusted with the job of protecting the public health. They check food to make sure that it is safe to consume. They check medications to make sure that quality control measures are being followed. They examine hospitals to ensure that facilities are safe. They license health care providers to protect us from harm.
We are oh so very vulnerable when we seek health care. We tell our doctor everything---about our drug use, our mental health issues, our sexual infidelities. We give our trust to---and place our lives in the hands of strangers when we go to the hospital emergency room.
A doctor who has committed a felony completely unrelated to medical practice is very likely to lose his or her license. Can we allow those who have committed war crimes to keep them? Whether or not you think that these folks are patriots, you must admit that they have shown a massive lack of human empathy. They have basic character flaws which make them unsafe as medical practitioners. Do you want to take the chance that one day you might (unknowingly) walk into the office of a doctor who used to torture for the CIA? Do you?
Do you want your son or daughter's life in the hands of a doctor who has proven himself willing to violate basic medical ethics, because a superior told him to? A professional does not answer to a "superior". A professional answers to his or her own conscience. Someone who once tortured because a superior told him to might recommend a surgery you do not need because a hospital administrator told him to. She might deny you a test you need because an insurance exec told her to. A health care professional who pleads "It wasn't me. I was just doing what I was told" is no longer a professional, because she is not there to serve you, she is there to serve someone else.