"I think that anything that causes a person to feel bad, particularly bad feelings that stem from internal causes, should be considered a disorder" What if som

"I think that anything that causes a person to feel bad, particularly bad feelings that stem from internal causes, should be considered a disorder" What if someone feels bad when they hurt someone else? Should that be considered a disorder? This is not just a theoretical question, as I've read that the military has been funding research in to whether drugs can be used to assuage feelings of guilt and distress some of their trained killers suffer from when they hurt/kill other people. The military wants their soldiers to be more efficient killers and pesky feelings of guilt or suffering when they hurt/kill others gets in the way of that. So should every source of negative feelings be extinguished, and should we all try to live life with a smile on our faces even when we engage in unethical or hurtful actions?