You should design impartial rules for everyone, and then act for yourself. But most people don't get to set the rules from on high. Thus the maxim was born, 'act as you would have everyone act'. If only everyone followed it, there would be no wars. If the generals and politicians were all Tanya they would not start a war, even if they were Francois.
But there is also such a thing as worker solidarity. Should you really want everyone to fight in war, no matter on which side? Should you want everyone-but-the-politicians to be Tanya? Is that really good for them? Are you going to realize you were fighting yourself all along, when you step into the paladin's aura?
Systems are built by people. Systems can and should be judged harshly, because they can be changed. People mostly respond to their circumstances, and they are not blameworthy for following the incentives that the system lays out in front of them.
It follows, then, that if people are to be blamed or punished for anything at all it should be for being who they are, and not for the behavior that was evoked by their environment.
Of course you should try to change the environment first. If you can make a set of rules that turns everyone into high performers, you deserve to be immortalized as a great and Good law-giver. But once you've done all you can, the remaining differences in outcomes are due to innate factors, and you must reward and punish those differences to incentivize people to change themselves. As ridiculous as it may sound, correctly incentivized people might even be capable of changing something about themselves they thought was immutable.
Nobody has the moral right to tell someone they should not exist as they are. Nobody except, maybe, that person themselves.
Tanya is someone who will join the army when conscripted, and fight a war when ordered, and she can tell good from evil but she firmly keeps those thoughts to herself. After all, that's how you get promoted rather than court-martialed for insubordination. And what would be the point of a junior officer protesting the very fact of a war? What could it possibly accomplish other than disposing of that one officer? Oh yes, she screams very loudly about the injustice and irrationality of war. She screams in her head where it's safe and nobody can hear her, as she flies into combat. As if protesting her own actions will make her less responsible for them, in the eyes of anyone but Pharasma who judges people's thoughts.
Maybe she should try being a different kind of person. One who, when conscripted, will simply... refuse to follow that rule, and find another way.
Not someone with a long and happy life, showered in awards and accolades. Not someone whose very presence makes thousands of strangers grateful that she is there to protect them. Not someone who risks her life for those strangers while telling herself that she has no choice.
Certainly, Tanya is selfish. Even in the aura of anatta, she doesn't want for everyone in the world to stop being selfish. That feels wrong.
When did she decide that being selfish meant seeking other people's approval?