"Christianity has rather a good effect on our society"

Crusades. Inquisition. Murder. Torture. Robbery. Child abuse. Which has had the best effect do you think?

Dave, you forgot to mention the rampant antisemitism acquiesced in for many decades by the Catholic Church before the Third Reich, which helped to soften people up for the Holocaust.   There was also the silence from Pius XII on the deportation of hundreds of Jews from under his nose to death camps, and the way in which this saintly man helped to facilitate the escape of Nazi war criminals to South America. Then there's Mother Teresa telling the poor that their lot was a virtue that they should not only not fight against but a virtue that they should actually celebrate (and she did much more than that). I hear she's in line for a sainthood, just in case anyone tells us that these things are all in the past. We could also mention the effect on the HIV epidemic in Africa, especially on women, of local holy men preaching against the use of condoms. Rather good, eh?