Christians die for their enemies, they don't kill them. If it weren't for the Christians, we would still have slavery and lynchings.
I'm afraid you couldn't be further from the truth. Jesus & friends might have died for their enemies (in the stories at least), but Christians tend not to.
On slavery. The Bible has rules of slavery and its teachings allow for slavery. It's late so I can't be bothered to dig out the teachings, but I can come back with them if you'd prefer?
But the defense for black slavery in America? The Curse of Ham was used. The explanation used to explain why there are 'black people' is because of the curse of Ham as the sons of Ham were cursed with blackened skin and they carried the sins of Ham. Black people had to be subject to white people because of the curse they inherited. That is what European & American Christians used to defend black slavery.
On killing. Christians still kill in the name of God and the bible today and are backed by what the bible teaches. Because I've talked about this before, I will quote myself to save time. This is about the violence/injustice done by Christians because of their Christian beliefs, which they use(d) the bible to support.
The Spanish Inquisition. Torturing people for God.
The Crusades. Invading countries and murdering its people in the holy land, for God.
The Witch Hunts. Many cruel and deadly methods of determining who's a witch and who isn't, followed by the death of said witches. In some countries, witches were even burned to death. What's even more disturbing about this is that this still goes on today. The bible instructs that witches be killed.
Exorcisms. People who could be diagnosed with a mental illness are treated as people who are possessed - this isn't healthy for them. And there's been several known cases where people have died because of an exorcism. It's not all throwing holy water and yelling "the power of Christ compels you!", they can get very physical.
JW - Blood Transfusions are unethical. Because of this sect, parents refuse their kids treatment where a Blood Transfusion would be necessary, which would save their life.
Christians who preach that natural disasters are caused by sin. Aid is given in terms of handing out bibles and scripture because they want to convert people who are in a disadvantaged situation, rather than offering them actual aid and support.
Christians who refuse medical treatment for themselves or their kids or other family members. Instead of calling the doctor they call a priest so they can be cured by prayer and not medicine. Because prayer doesn't work, this often leads to people's conditions getting worse and even dying.
Christians who prefer to teach abstinence over safe sex. People are immoral because they have sex before marriage, so they'd rather teach kids about NOT having sex, but finding they do it regardless. In some faith even contraception is *wrong* meaning people end up getting pregnant when they're too young or contracted an STD. Heck, because of lack of propr education, they don't know what 'safe' sex is as Christians are so opposed to teachings kids about 'sex'. The important lesson for them is: don't do it until you're married.
Christians who are against women's health. Because of their strong anti-abortion views. They base their understanding of a human on when they believe they get a "soul" brain activitiy or stages of development where they're just tissue doesn't matter. So if there's complications, which would damage women's health? That's right, they can't have an abortion legally. They might get one illegally, which can be dangerous.
People who believe they are cured by prayer and thus don't get medical treatment. There was even a thread on this not-so-long ago. People suffering from AIDs told by the Church they were cured.
The view that non-believers are evil. This results in discrimination, even on violent levels. There's atheists here who can relate a story to that. We even have the story of Goodkat, a non-believer who used to post here who stopped because of his violently aggressive and bigoted Christian father.
The view that homosexuals are an abomination. Plenty of discrimination against gays. Still. Violence towards them too, plenty of that. Parents who so adamently believe their son or daughter is an abomination they force their religious guilt trips on to them, leading them into hating themselves, into depression and even suicide.
The Curse of Ham. Before slavery was abolished, what did Christians used to say? It's okay to enslave black people because they have been marked with the Curse of Ham, hence their skin is black. Slavery is also supported by the bible.
Killing Abortion Doctors because life is sacred. Related to, life begins at conception, thanks to Christians believing the soul is formed then, so in their mind all they're doing is killing murderers and defending innocents.
These are all things that are off of the top of my head and the worrying thing is, there's a lot of things I am missing. Bear in mind I am NOT listing bad things Christians have done/still do (otherwise I would have included Hitler & Nazism) but bad things Christians have done/still do BECAUSE of their religion. You wouldn't believe the amout of bible quotes people use to support the above.
Also, I feel I should mention the gay atheist, Alan Turing. The only thing that was 'destructive' about his life was the prejudice made against him for being a homosexual. For a brief summary of his life: http://www.whof.net/2012alanturingyear.htm.
Then consider many of the bible's actual teachings on violence (I can come back with biblical quotes if it'd help), most of it is Old Testament stuff, but Jesus himself talked about how people should follow the Old Testament, there are quote from Jesus from different gospels to back that up. I'd say one that sticks out in my mind is the one because how he hasn't come to change the law but to deliver it.
But what bothers me is that we have to keep telling Christians of attrocities done in the name of the religion because they are blind as to their religion's history and even what goes on today.. Not so long ago I was talking to a guy somewhere who was so convinced that no ill had been done as a result of his religion that he challenged me to find 1 single example of where Christians have hurt people. So I brought up the witch hunts in Nigeria. Evangelical Church, literalist interpretation of the bible, bible says there's witches, people believe the bible's true, bible says kill witches, so they kill anybody they think is a witch. The guy's response. "They're not true Christians" and yet they were only doing what they read in the bible and told that the bible was the infallible word of God and must be taken literally.
The irony is, the same guy believes Islam as a whole is evil because of what the Qu'ran says. But the Bible and Qu'ran aren't so different. Usually the logic is, if it's a Christian doing screwed up shit, it's because they're not true Christians, but if it's a Muslim, it's because Islam is a religion of death as it's what the Qu'ran teaches. Yet non-extremist Muslims use the exact same defense as Christians when talking about the attrocities done for their religion. It seems people live in denial about their own religions, just because they feel how they choose to follow it is good and righteous.