In a way I feel you are being far too lenient on McCain. Many Nazis were hanged for warmongering (more specifically the crime of waging aggressive wars). The lead prosecutor at the Nuremburg trials was an American named Robert Jackson. In closing arguments he said that no country or their leaders is beyond the law and that if someday his own countrymen would commit similar crimes he would feel no compunction in having them hanged.
If you don’t feel terrible about stiff Nazis swinging from the gallows why should you feel bad about anyone else who have committed the same kind of crime? Because of blind tribalism. Because of racism. McCain is part of our tribe, not subject to moral and legal rules other people in other countries must follow. Brown skinned babies or Asian babies (people McCain has been killing for over 50 years) are not fully human like those lightskinned babies that died during the Holocaust.