Sorry, I don’t see any evidence for that. Also, if we speak about the Crusaders, I don’t think it had almost anything to do with Christianity, if Christianity means the teachings of Jesus. It is possible that people have done many evil things also in the name of Christianity, but I think it is really about greed and lust for power, not about Christianity. Reason why Christianity is not used anymore is that people have learned something about what the Bible tells and it can’t be used anymore, like when people were more ignorant. That is why other excuses are used, like for example “terrorism”.
Religions are only one way to gain power and it itself tells about the evilness of people how they use even good ideas for evil purposes. Nowadays, in western countries, there are other than Biblical excuses for evil actions. But the people who rule are as evil as they have been, or worse, if we look for example what happens in Venezuela, India, China, Yemen, Syria, Libya… …there is endless amount of violence and other wrong actions. And western countries are also involved and perhaps often the main guilty.
I don’t think people are kinder, they are more evil than ever, because nowadays moral has changed, what was before considered bad, is nowadays good and what was virtue, is stupid and avoided.
I think this has happened:
Because iniquity will be multiplied, the love of many will grow cold.
Matt. 24:12