God's second commandment is that we should "love our neighbour" in Matthew 22:37-40, Mark 12:30-31 & Luke 10:27.
So this is a key tenet in the Christian faith, which is intrinsic to anybody's Christian identity.
So for anyone to disregard such a key tenet means that they will not be Christian as such.
Those who hate (or dislike) another soul by virtue of their colour cannot be called Christian as such.
By definition, Christians are not racist at all, but those who are racist cannot be called Christian.
Do you agree that it's impossible to be Christian and racist at the same time?
Below are some examples of why racism has been so prevalent in Christianity. Many throughout history have seen Christianity as sanctioning racism and slavery. So, it comes as no surprise to me that many racists identify with Christianity even today. As a Christian myself, it makes me very sad that passages like the ones below have not been explicitly struck down as being out-of-line with Christian ideals, but what are you gonna do.
"In the past, many believed the mark on Cain to be dark skin—that God changed the color of Cain's skin to black in order to identify him. Since Cain also received a curse, the belief that the mark was black skin caused many to believe that people of dark skin were cursed. Many used the “mark of Cain” teaching as a justification for the African slave trade and discrimination against people with black/dark skin. This interpretation of the mark of Cain is completely unbiblical. Nowhere in the Hebrew Scriptures is 'owth used to refer to skin color. The curse on Cain in Genesis chapter 4 was on Cain himself. Nothing is said of Cain's curse being passed on to his descendants. There is absolutely no biblical basis to claim that Cain's descendants had dark skin. Further, unless one of Noah's sons' wives was a descendant of Cain (possible but unlikely), Cain's line was terminated by the Flood."
What was the mark that God put on Cain (Genesis 4:15)?
“[Slavery] was established by decree of Almighty God…it is sanctioned in the Bible, in both Testaments, from Genesis to Revelation.” Jefferson Davis, President of the Confederate States of America.
“There is not one verse in the Bible inhibiting slavery, but many regulating it. It is not then, we conclude, immoral.” Rev. Alexander Campbell
“You may purchase male or female slaves from among the foreigners who live among you. You may also purchase the children of such resident foreigners, including those who have been born in your land. You may treat them as your property, passing them on to your children as a permanent inheritance. You may treat your slaves like this, but the people of Israel, your relatives, must never be treated this way.” (Leviticus 25:44-46)
“When a man strikes his male or female slave with a rod so hard that the slave dies under his hand, he shall be punished. If, however, the slave survives for a day or two, he is not to be punished, since the slave is his own property.” (Exodus 21:20-21)
“Slaves, obey your earthly masters with deep respect and fear. Serve them sincerely as you would serve Christ.” (Ephesians 6:5)
“Christians who are slaves should give their masters full respect so that the name of God and his teaching will not be shamed. If your master is a Christian, that is no excuse for being disrespectful. You should work all the harder because you are helping another believer by your efforts.” (1 Timothy 6:1-2)