Like any oxymoron, it seems contradictory, but is nevertheless true. Sadly, some people have interpreted the teachings of Jesus to mean that non-Christians are evil, not to mention gays and lesbians, etc.

The same belief system which allowed people to be "Christian" and support slavery (and later segregation) at the same time.

The belief system that was one of the main foundations of the Civil Rights Movement. The people in Birmingham who were attacked by dogs came from a church, SCLC (Southern Christian Leadership Conference) was one of the main Civil Rights groups, and was headed by Martin Luther King, Jr., a Baptist minister. Point being that, yes, throughout history a lot of people have used Christianity to their own ends, but that doesn't invalidate Christianity. To quote (well, actually, paraphrase) Stokely Charmichael: "You can't judge Christianity by Christians, you judge it on its principles."