This is a complex issue for me, as I am more or less a non-practicing historian at the moment. There are two sides to it.
- You really have to consider the world people live in, and judge their actions with that knowledge in mind. To often we forget that there is a link between the material world people live in, and the morality they are capable of practicing. Too often, being kind to those fortunate meant death in the past, where it would mean only inconvenience today.
1a. An Icelandic farmer in the “saga age” who refused to kill his neighbors children over a perceived insult would soon be unable to protect his own children - because he was now known to be weak. We should consider that before we call him a psychopathic killer.
2a. The inquisition saved far more lives than it took. In fact, it was initially set up to stop people just killing heretics outright. Most people sent to an inquisition got away with a slap on the wrist and some bible lessons, and were thereafter safe from secular legal action. When you look at it like that, the image becomes less one-sided. I don’t think most inquisitors were evil people, I think they were more or less analogous to people in legal professions today. Particularly when compared to countries who still practice the death penalty in this day and age, who really don’t have an excuse.
- On the other hand, if you always judge people by the standards of their time, you can end up in a mindset where you look at people from the past as stupid, or not capable of complex thought or emotion. I’ll use American black slavery as an example (since most people will have an emotional response to it, which is what I’m after here), and contrast and compare with other events.
2a. The people who stuffed a ship full of suffering people, mistreated them, starved them, dumped the dead and dying overboard, and sold them to a short brutal life of pain and suffering knew damn well what they were doing, and it is fair to judge them as evil by our standards.
The people who bought a healthy slave, had a fuzzy idea of what went on in the slave trade, and personally treated them well are slightly different case, and might be treated more kindly by us. After all, many people now buy clothes made by foreign workers whose conditions are comparable to what the slaves went through - at least the slave owners were honest.
2b. The Bryant and May match factory, until a strike in 1888, insisted on using white phosphorus in their matches. This caused a condition known as phossy jaw, a painful rotting of the jawbone. In the last stages of the illness, the bone glowed in the dark. At that point, the person might be saved by amputation, but most died. The workers were mainly teen girls, who worked long hours standing up in awful conditions, were paid almost nothing and treated like worthless trash. A girl was famously fined for letting go of a piece of machinery to save her fingers. She was told “never mind your fingers - take care of the machines!”.
The people who ran these factories knew damn well what they were doing. As did the politicians who for so long refused to ban white phosphorus when red works just as well in matches.
But the people who just bought the matches, and complained when the price went up slightly after better wages and red phosphorus were forced trough? Maybe we should be more understanding, and think of the log in our own eye.