The short answer is that liberals have disordered minds, as do Marxists, Communists, Socialists who play the blame game and believe that 7th century religious ideology can be assimilated into Western Civilization.
They believe that terrorist activity is but a "bump in the road" as Germany leads us to the New World Order with open borders. Think of the money we will save if no one needs a passport!
Paul the Apostle would agree:
Romans 1:28,29.
28 Furthermore, because they did not think it worthwhile to keep knowing God fully, God delivered them to degraded minds to perform acts that should not be done. 29 They have become filled with every kind of wickedness, evil, greed, and depravity.