IMO these christian liberals confuse themselves with God. They remind me of Sir Robin at the bridge in Monty Python and the Holy Grail. They see evil in the world that needs fixing and say "That's Easy!" Then off they go over the cliff not realizing that it is their all too human conceit that is their undoing.
That's a great point. (I love that movie!) Yes, I believe that the root of liberalism is a God complex. "I can rid the earth of poverty." "I can make the world equal." "I can use government to advance society."