When bad people are alive, you can oppose them. But as soon as they are gone, they're not your enemies any more. They're just people who once were, but now are not. Memories.
The quote - there are no enemies in death - comes from "Lone Wolf and Cub," a favorite serious of mine. You can see me reviewing a bit of it at the entry "Rule an Empire, Fistful of Rice."
After some mortal enemies is vanquished, the protagonist gives them a respectful burial. When asked why, he explains that there are no enemies in death.
It's easy to get caught up in cheering for one side of history, but your feelings don't affect what's already happened. And strong feelings can easily blind you from figuring out what really happened.
It may not always be possible, but it would be good for you if you can become dispassionate in analyzing long dead eras.
Some of my bloodlines are Russian/Polish - Eastern European - but I try to be dispassionate about the Eastern Front of WWII. It makes me better able to study it, understand it, know how it happened.
Some of my descent is Irish, and I try to be dispassionate about Oliver Cromwell, so as to fully understand what happened there.
Some of my descent is Spanish, and I'm an American - and again, I don't take rooting sides in the Spanish-American War.
I hold Alexander the Greater in much less respect than most people. A brilliant tactician, but a very bad statesman with very little regard for the lives of his soldiers. But again, he's not be hated, or felt particularly strongly about. There are no enemies in death.
The same would go with Shaka Zulu or Genghis Khan. Those three - Alexander, Shaka, Genghis - actually had remarkably similar tactics. They moved to lighter, more mobile forces, a militant culture that began training their soldiers at a younger age, a more brutal and less honorable style of combat, and heavy conscription/recruiting of defeated enemies in order to press forwards quickly after a victory instead of consolidating. They were all able to move quickly because they didn't care about their own casualties - they'd use their soldiers as shock troops, and then recruit from the defeated to fill their ranks back up.
The exact methods were a little different, but there were many similarities. None of them cared for their soldier's lives. All of them were competent tacticians, but not particularly gifted statesmen. Under their reigns, they won many great battles, but destroyed lots of culture and commerce.
But there are no enemies in death! They can all be studied. We can learn from Alexander and Shaka and Genghis, and Hitler and Stalin, and Oliver Cromwell and Theodore Roosevelt.
While I find them incredibly distasteful, much can be learned from Castro and Guevara and Pol Pot and Kim Il-Sung.
It's easy and fun to study the "good guys" you respect, and boo the bad sides in history. But you're limiting your education and understanding if you do so. The Soviet Union was probably the greatest threat to the extinction of humanity of all time, and that whole world should have been fought even harder than it was at the time. But now that it's passed, it can be studied and understood. Slave labor, collectivization, that whole system is morally bankrupt... but it is dead, and there are no enemies in death. The ruins of the Soviet Empire can be dug through to learn about its history. We can adopt the (few) good practices that came from the place in arms and science, and we can study where and how it fell.
It's too tempting, too easy to boo the other side. To that extent, I'm thankful I have English and Irish blood. Both sides massacred on each other, but the English were stronger and won, and dominated Ireland. For someone with pure Irish blood, it's hard not to hate Oliver Cromwell. Certainly, I don't like the guy at all. But I set aside any ill feelings I have in order to study him. Could you do that if you were 100% Irish? I think you could. You don't need to spit when his name is said, or have your blood boil. It doesn't hurt him - he's dead - and it doesn't help you. There are no enemies in death. Study and understand and why things happened how they happened.
There are no enemies in death! Study everything, even what you find distasteful. I have a United States Naval officer's translation of Mao's "On Guerella Warfare" on my Kindle, and I'll get around to reading it sooner or later. That era has passed, but to learn how to defeat bad people, you need to study bad people. Learn their methods, friend or foe. Hating them doesn't harm them after they're gone - it only stunts your own development and blocks large amounts of potential lessons.
There are no enemies in death.
"The strong manly ones in life are those who understand the meaning of the word patience. Patience means restraining one's inclinations. There are seven emotions: joy, anger, anxiety, love, grief, fear, and hate, and if a man does not give way to these he can be called patient. I am not as strong as I might be, but I have long known and practiced patience. And if my descendants wish to be as I am, they must study patience." -Tokugawa Ieyasu
In the late 1400's, the ruling Ashikaga Shogunate of Japan became weak and lost its hold over the country. A many-sided civil war broke out, thus beginning the "Sengoku Period" - known as one of the most bloody and lawless periods in Japanese history, but also an era of some incredibly most heroic leadership.
Eventually, "Three Great Unifiers" came to power and ended the conflict through victory. These three were Oda Nobugana, Hideyoshi Toyotomi, and Tokugawa Ieyasu.
In the end, Tokugawa Ieyasu won, and his family ruled Japan for the next 250 years. However, he's probably the least popular of the three great unifiers in Japan.
Nobunaga is popular for having an incredibly fierce, martial, masculine spirit. At one point, the warrior-monks of the Honganji allied themselves against Nobunaga and harried, harassed, and ambushed his armies. The Honganji provided supplies, spies, and information for Nobunaga's enemies and sometimes faced them in direct combat.
I recently purchased an indie(?) darling(?) on Steam called Magicka. Recently released by Arrowhead Game Studios, Magicka is satirical action-adventure game about mages, saving the world, and vampires, or not.
There are a few great reviews out there which cover the game in detail, so I'll kind of skim over that and instead get to the meat (or veggie burger for you vegetarians) of what I'd like to talk about today: Dominant Strategies. Magicka is a great example of a game that fails to prevent dominant strategies from occurring, and why this matters.
A Dominant Strategy is a strategy or method of acting within a game/life which is vastly superior to the majority of other options in most contexts.
As humans, we are wired to use optimal strategies. That is, if we know a better way of doing something, we prefer to use that method. After all, why take longer or use more effort when you can do it faster or with less effort? So! If a game has one or two Dominant Strategies, it doesn't matter how many other choices are available, the human mind ends up categorizing them as "Optimal vs Sub-Optimal". If you always pick the optimal solution, the game can quickly become boring; if you choose a sub-optimal solution, you may feel bad because you aren't doing the best that you can.
Most well balanced games include abilities which are superior in specific situations, but weak in others. This means the player must figure out what abilities to use based on the situation - their choice is important. Other games have abilities which are roughly equal in overall power, but different in effect (setting people on fire vs electrocuting them). Again, this leads to varied play-styles and infuses the players choices with import. Let's check out Magicka as a case study.