You do understand the difference between ‘use’ and ‘misuse’, don’t you?
Do we really need to get into a discussion of how many died at the hand of atheist regimes in the 20th century alone?
There have been times in the Christian church where those who have claimed to follow Christ have done horrible things. They have done these things not because Christ teaches them, but because they have not listened to the word of God. As is frequently established in history when anyone comes into complete political and military control abuse almost always follows. The Inquisition was a Roman Catholic invention intended to root out all sorts of "heresies." The Inquisition used torturous means to force confessions out of people. Thousands were killed mercilessly and unjustly. The Protestant Reformation distances itself from the Catholic Inquisition, yet has its own sordid history.
this does not mean that Christianity is false anymore than the police force is false because one or two cops did bad things in the name of the law. Instead of looking at the two cops, the whole of the police force, its goals, other cops, and its history of sacrifice and protection must be examined as well. The same holds true for Christianity. It has a great history of helping countless people, establishing orphanages, building shelters, helping famine-ravaged countries, and seeks to aid the downtrodden.
If anyone wishes to condemn Christianity because of the failures of its members, then will they also look at its successes and approve of Christianity? It would only be fair to look at the whole of Christian history and more importantly at what the Bible actually teaches, in particular the New Testament, from which Christianity is derived.