IMO Sora isn't shown as someone socially ackward, but as someone who didn't care for the shallow real life. In his childhood he is able to put on a persona to interact with others, just like he does in the fantasy world. But during his NEET times, he chose not to interact with other.
This article gives more insight on Sora and Shiro's character. Plus information on their names.
http://yaranakya.wordpress.com/2014/...-game-no-life/