Erick Erickson nails it:
Secular leftists and Islamists are both of this world. Christians may be traveling through, but we are most definitely not of the world. In fact, Christ commands us to throw off our ties to this world. But the things of this world love this world and hate the things of God. That’s why secular leftism can embrace both activist homosexuals and activist muslims when the latter would, when true to their faith, be happy to kill the former.
I wonder how Jews fit into this framework?