Here is a game, the greatest game, imho. I think you will like it and I think you will enjoy the outcome, the outcome doesn't directly agree with me and the game talks about the Christmas truce.
War itself is not evil. When someone owns a slave, there is already violence encoded in that relationship. The slave owner is already at war with the slave. When the slave fights back, that is just. The slave owner is a child of someone, too. Status of having a mother who cares about you has no bearing on justice. Serial killers have mothers, too.
You can say it is a war between countries and not their people, but it is people who are firing those guns and people building those weapons and people producing war media and people relaying commands to soldiers.
Your opinion is one of privilege. People with privilege can claim that humanity means "not fighting back." You can believe that because you exist in a country where people can fight back on your behalf. Privilege is the ability to have beliefs without having to deal with the consequences of those beliefs. You feel entitled to peace, but can't see that peace isn't always your choice you get to make, but a choice someone else makes.
In the game of prisoners dilemma, someone can choose to defect, you cannot make them cooperate. When someone defects against you, having empathy for them and choosing to "cooperate" just means you lose. "If you want peace, then prepare for war..." if you aren't prepared for war, then you are showing that when someone defects they can win.
You frame the war around helpless people being walked to their death's by corrupt aristocracies, but you fail to frame war with justice and ask what justice requires.
To Ukrainians it does not matter if it is the Russian government or the Russian people invading their lands. If you cannot see their plight, it is you who do not have humanity.
In regards to the Christmas truce, I do not believe Germany was fighting a fundamentally genocidal war while Russia is fighting a genocidal war against Ukraine. I don't think you can equate those.
I say this as someone who considers themselves deeply liberal, who has a history of thinking like you do and who has now come to the conclusion that what I thought (what you are saying) is very wrong: Check your privilege.
Have some compassion. Countless Russians are being conscripted to fight a war they don't want to. These are all children of someone.
That things like https://en.wikipedia.org/wiki/Christmas_truce can happen speaks volumes about this. The wars are between countries, not their people.
Don't lose your humanity.