"And you shall be hated by all men for my name's sake (Mathew 24:9)."
This verse is the main problem. If a Christian does anything in the name of their religion and people react negatively to it, they take it as prophetic proof that they are true Christians. If you protest soldiers funerals in the name of God and people protest you, well, this proves you are a true Christian because you are being "persecuted". If you bomb an abortion clinic, if you violate the establishment clause, if you talk poorly about Jews, and people react negatively, then it's proof you're a true Christian. I bet if some Christian slept with goats and the rancher who owned them got mad, the Christian who slept with goats would say that the rancher's anger is prophetic evidence that the Christian was doing the Lord's work.