"There are five dangerous traits of a general:
He who is reckless can be killed.
He who is cowardly can be captured.
He who is quick tempered can be insulted.
He who is moral can be shamed.
He who is fond of the people can be worried." Sun Tzu
You might say, now wait a minute, doesn't Sun Tzu believe in morality? Yes, he does.
Let me explain. Someone who is moral is beneficial in almost all cases. Thus as a default a situation will likely call for a leader who is moral. However, there will be situations where a moral leader isn't as effective as someone who is amoral.
For example, if a leader's principle is to always tell the truth, he or she will put innocent people in danger when he exposes their exact whereabouts. Someone who is amoral will tell a straight-up lie pointing to a location far away from the exact location.
Another example is telling a white lie in order to not hurt another person's feelings in the hopes that long-term improvements are more likely with patient encouragement than trigger-happy criticism.
Therefore, deception is usually a more effective means of achieving advantage than honest brute force.
You might say, now wait a minute, a leader can indeed be moral when he refuses to state the exact location of innocent people without telling a lie. A leader can indeed refuse to answer to avoid telling a white lie. However, is keeping quiet -- which nonetheless exposes the harsh truth through inference -- truly as effective as telling a convincing white lie? Furthermore, your aim is to benefit others, not yourself. So the more effective you are, the more they will benefit.
But I digress.
Sun Tzu specifically mentions possibly an enemy can shame a leader into acting moral even at the expense of the people she is trying to protect and promote. For a leader to be truly effective, she must have a sufficient number of options. If the leader limits her options to value her morals over achieving the outcome with the least amount of cost to lives, suffering, and treasure, then the leader acts selfishly and thus foolishly. She is no treasure to the nation.
This also means she loses sight of her purpose and value to society. History is filled with people who got lost in the forest because they focused too much on the trees.
As the Bible advised, "Be shrewd as serpents but innocent as doves." It means knowing what works and what doesn't in the overall goal of achieving a benevolent result.
Ultimately, if the leader suffers the shame of being amoral instead of appearing moral, then so be it. Let them mock and criticize. However, you know who you are. You don't depend upon others to give you value. The entire world can all call a horse a donkey but the horse remains a horse of course.
So stay the course and refuse to allow people and things distract you from your mission in life. Hurt feelings are illusory and ephemeral, but having the emotional fortitude to help others when they need help -- even when they don't deserve it -- is truly powerful, tangible, and fulfilling.