Just as they say to beware of false prophets, so too do we need to beware of false Christians. I agree with you on all points. Well said.

On another tangent, I have written about how odd it is that Martin Luther King arrived at such a different conclusion as so many racist Christians have with regard to the supposed supremacy of whites. As you say, racists must not be truly Christian, for I doubt Christ said anything about the color of skin with regard to whom shall be saved (I'm not a Christian and have never read the Bible all the way through but I'll take it on King's word that he's right).