The Bible does not teach the horrible practices that some have committed in its name. It is true that it's possible that religion can produce evil, and generally when we look closer at the details it produces evil because the individual people [Christians] are actually living in rejection of the tenets of Christianity and a rejection of the God that they are supposed to be following. So it [religion] can produce evil, but the historical fact is that outright rejection of God and institutionalizing of atheism (non-religious practices) actually does produce evil on incredible levels. We're talking about tens of millions of people as a result of the rejection of God. For example: the Inquisitions, Crusades, Salem Witch Trials killed about anywhere from 40,000 to 80,000 persons combined (World Book Encyclopedia and Encyclopedia Americana), and the church is liable for the unjustified murder of about (taking the high number here) 300,000-women over about a 300 year period. A blight on Christianity? Certainly. Something wrong? Dismally wrong. A tragedy? Of course. Millions and millions of people killed? No. The numbers are tragic, but pale in comparison to the statistics of what non-religious criminals have committed); the Chinese regime of Mao Tse Tung, 60 million [+] dead (1945-1965), Stalin and Khrushchev, 66 million dead (USSR 1917-1959), Khmer Rouge (Cambodia 1975-1979) and Pol Pot, one-third of the populations dead, etc, etc. The difference here is that these non-God movements are merely living out their worldview, the struggle for power, survival of the fittest and all that, no evolutionary/naturalistic natural law is being violated in other words (as non-theists reduce everything to natural law -- materialism). However, and this is key, when people have misused the Christian religion for personal gain, they are in direct violation to what Christ taught, as well as Natural Law.
(A condensing of Gregory Koukl's, "The Real Murderers: Atheism or Christianity?")