They may say they don't believe terrorism in the name of God is Christian behaviour, but then they turn their eyes from what their "Christian" leaders have done in other countries, they enact violence against the LGBT community, they spread fear and hate in the name of "religious freedom", and consistently defy the very teachings of Christ in favour of cherry-picking the Old Testament laws that the New Covenant freed them of.
It's not ALL Christians, of course, but Abrahamic religions serve as a means of righteous justification for the hostility and fear they are already harboring. They think they have a divine right and responsibility to rid the world of sin making them far more volatile. No religion should be respected that would either condone or be indifferent to such dangerous conviction.
If their concept of apocalypse is true they'll be the ones who make it happen. We see devastation and despair while they see silver linings. Why else would they want greater political influence and control? They want to mandate "Christian values" and turn America (which never has been a Christian nation) into a theocracy.