It only makes sense when the spiritual paradigm is observed. The Left serves the god of this world, their blindness not alleviated by the Light of Christ. Jesus said that Satan's kingdom is a united kingdom, the various players working often in unwitting concert. Muslims who also serve Satan benefit from the blindness of the Left who will advocate for them even to confound their own interests.
Standard Disclaimer: I believe in no god or gods.
The motives of the left are far more visceral; a lust for power. The left has fought a 40 year war to utterly crush the culture of America, and has been largely successful. To the left, fealty to the family is greatest impediment to absolute obedience to the state. Lenin wrote in 1920 that men will support brothers and children over their rightful rulers in the state, the answer was to place children in communal learning (it takes a village) and divide families away from the traditional homestead.
This is the same war the left has waged in America, for the same reason. Even the sexual promiscuity the left has pushed onto children is designed to destroy the nuclear family structure.
The left seeks absolute power, those like Nosmo and Shortbus believe they will personally benefit from their gang holding the reigns of power, thus they fight the concepts of liberty and individualism in hopes of riding the coat-tails of their rulers.
There is nothing supernatural or mystical about this - just the age old lust to rule over one's fellow man.