It is true that Christians sometimes lie as well. 

The difference is that a Christian believes in the existence of God and also believes in the existence of Truth.  As a result, a Christian is going against his or her belief system if he or she lies.  Liberalism has no such conflict.  When they throw out the Biblical authority and put the human imagination in place of the Bible as the authority, then anything goes.  If that were to be the case, then winning would be everything.  If you look at life through the eyes of liberalism there is truly no right or wrong, so winning, pleasure, and power is the meaning of life to the liberal.