You have more than one point in your post. I will try to address them, but I hope you can forgive me if I miss one or two.
Do we have differing definitions of "Christian"? What is a Christian to you?
Yes, Christians do differ on issues, but they differ usually because they've started from different points of view. They have different conclusions about the world to begin with, thus they have certain differences in their worldviews, which is part of the point that I made originally. Worldview is important. People who upheld Jim Crow, sometimes violently, usually weren't Christians. Their worldview was one that can't be found in the Bible. It came from somewhere else. A Biblical worldview would not do as you have pointed out that some did.
You paint the world with a fairly broad brush, it seems to me. I have a limited experience with you, this being the first time that I know of that we've exchanged ideas, but still it seems that you blame much on many who do not deserve it. The vast majority of people who follow the Bible have never even wanted to lynch anyone, let alone do so. Some of us are even against the death penalty, let alone lynching. Life is important enough--sacred, in fact--that no human has the right to take it from another. So, not all of us on one side of an issue are going to be like others, especially those who do not share our religion.
Those you mention, who defended slavery, were not doing so because of the Bible but in spite of it. There were northern Christians prior to the Civil War, you'll remember, who agitated for abolition and even worked the Underground railroad, and did so because they saw in the Bible that we are one before God. Why do you not emphasize them instead of the others?
There are still many who invoke the Bible and the name of God when it suits them but don't really mean it, because they ignore it when it's inconvenient to them. It's not the Bible's fault that some people misuse it, and it's not all Christians on one side of an issue who will be as bad as other people who just happen to agree with them.
So your use of the term "using" the Bible is right--they used it. They didn't believe it. So if they were Christians, they were by definition bad ones. Many of them weren't Christians at all, for of some who use the name of Christ, Jesus himself said, "Why do you call me Lord but don't do what I say?"
Now, a question: why can't you stand next to Dick Cheney now? I mean, besides the obvious practical problems of bodyguards and such? There is such a thing as loving one's enemy in the Bible. If we are to love our enemies, and if we are to pray for those in authority, then why can't we stand next to them?
Law is about morality. What you mention, power and money, is a morality. Not an especially good one, but a morality nonetheless. Some people deviously use the law to their own advantage, this is true, but that's because their morality happens to be a bad one, a selfish one. But all law--all of it--is about morality.
Can you name one law that doesn't have as its root a view of right and wrong, that tries to establish that which is right and wrong?