Socialism comes in many forms. It can democratic and autocratic and in between. I would even say Jesus was a socialist. He cared for the poor and said that we would be judged by our treatment of the poor, hungry, homeless,  and sick. It was his only comment on what basis we would be judged. 
I think your understanding of giving "a cup of water" in Christ's name to gain a reward falls short of our need to do it because of our love for God and for others.